CA2222475A1 - Protegrins - Google Patents

Abstract

Cationic antimicrobial and virus-neutralizing peptides having 16 to 18 amino acids and comprising 0-4 cysteines are provided as five native protegrins isolated from porcine leukocyte granules having two cystine bridges or as various protegrin analogs having no, or a single, cystine bridge. Native protegrins have, and analogs may have, carboxyl-terminal amidation and analogs may optionally be prepared in amino-terminal acylated and/or cysteine-stabilized and/or carboxyl-terminal esterified forms. Any of the 1-4 native cysteines may be replaced with a hydrophobic or a small amino acid and various substituents are disclosed for the remaining 12-16 positions. Recombinant host cells and methods for production are disclosed, as well as pharmaceutical compositions, compositions for agricultural application, and methods for bacteriostatic, virus-neutralizing, and endotoxin-inactivating use of native protegrins and their analogs.

Description

CA 0222247~ 1997-11-26 W 096~'37'5~8 PCTrUS96~7S94 PRQTEGRINS

This in~rention was made with funding from NIH Grant No.
A12~839. The U.S. Government has certain rights in this 5 invention.

Technical Field The inv~ntion relates to the field of antibiotic peptides. In particular, the invention concerns short pepl~ides, sonne of which are isolated from porcine leu]~ocytes, t;hat have a wide range of antimicrobial act:ivities.

Bac3~round A~t ~ne of t:he defense mech~n;.qms against infection by both animals and plants is the production of peptides that have ant:imicrobia] and antiviral activity. Various classes of theE3e peptidc!s have been isolated from tissues both of plants and ~n; m~l 8. Olle well known class of such peptides is t:he tachyE)lesins which were first isolated from the hemc~cytes of the horseshoe crab as described by N~k~mll~a, T.
et al . ~ Biol Chem (19~8) 263:16709-16713. This article desc~ribed the initial tachyplesin isolated, Tachyplesin I, fronn the Japanese species. Tachyplesin I is a 17-amino acid amidated peptide cont~;n;ng four cysteine residues providing two intramolecular cystine bonds. A later article by this group, Miyata, T. et al. J Biochem (1989) 106:663-668, repor~ the isolation of a second tachyplesin, Tachyplesin II, consisting of 17 residues amidated at the C-terminus, alsc) cont~;n;ng four cysteine residues and two intramolecular disulfide bonds. Two additional 18-mers, cal].e~ polyrh~mll~ins, highly homologous to Tachyplesin II
and cont~;n;ng the same positions for the four cysteine resi.dues, were also isolated from the American horseshoe crab. Polyphemusin I and Polyphemusin II differ from each other only in the replacement of one arginine residue by a lysine. All of the peptides were described as having antifungal and antibacterial activity. A later article by CA 0222247~ l997-ll-26 W 096t37508 PCTrUSg-~7 Murakami, T. e t al . Chemothera~y (1991) 37:327-334, describes the anti~iral activity of the tachyplesins with respect to vesicular stomatitis virus; Herpes Simplex Virus I & II, Adenovirus I, Reovirus II and Poliovirus I were resistant to inactivation by Tachyplesin I. Morimoto, M. et al. Chemothera~Y (1991) 37:206-211, found that Tachyplesin I
was inhibitory to Human Immunodeficiency Virus. This anti-HIV activity was found also to be possessed by a synthetic analog of Poly~h~mll~in II as described by Nakashima, H. et al. Antimicrobial Aqents and Chemotherapy (1992) 1249-1255.
Antiviral peptides have also been found in rabbit leukocytes as reported by Lehrer, R. I . et al . J Virol (1985) 54:467-472.

Other important classes of cysteine-con~in;ng antimicrobial peptides include the defensins, ,13-defensins and insect defensins. The defensins are somewhat longer peptides characterized by six invariant cysteines and three intramolecular cystine disulfide bonds. Defensins were described by Lehrer, R.I. et al. Cell (1991) 64:229-230;
Lehrer, R.I. et al. Ann Rev Immunol (1993) 11:105-128. A
review of m~mm~lian-derived defensins by Lehrer, R.I. et al .
is found in Annual Review Immunol (1993) 11:105-128; three patents have issued on the defensins: U.S. 4,705,777; U.S.
4,659,692; and U.S. 4,543,252. DeEensins have been found in the polymorphonucleated neutrophils (PMN) of hllm~n~ and of several other ~n;m~s~ as well as in rabbit pulmonary alveolar macrophages, and in murine small intestinal epithelial (Paneth) cells and in correspo~;ng cells in hllm;~n ~, ,13-Defensins are found in bovine respiratory epithelial cells, bovine granulocytes and avian leukocytes. See Selsted, M.E. et al. J Biol Chem (1993) 288:6641-6648 and Diamond, G. et al. Proc Natl Acad Sci (USA) (1991) 88:3952-3958. Insect defensins have been reported by Lambert, J. et al. Proc Natl Acad Sci (USA) (1989) 88:262-265.
Antifungal and antibacterial peptides and proteins have also been found in plants (Broekaert, W.F. et al .

CA 0222247~ 1997-11-26 W O961;37C;08 PCT~US96/07S94 8iochemistry (1992) 31:4308-4314) as reviewed by Cornelissen, B.J.C. et al. Plant Physiol (1993) 101:709-712.
ExprelYsion systems for the production of such peptides have been lused to transform plants to protect the plants against such infection as described, for example, by Haln, R. et al.
Nature (1993) 361:153-156.
The pre~ent invention provides a new class of antimicrobial and antiviral peptides, designated "protegrins" herein, representative members of which have been isolated from porcine leukocytes. These peptides are usei-ul as antibacterial antiviral and antifungal agents in bot~l ]?lants aLnd ;:ln~ m:~l 8 .
The isolation of the protegrin peptides of the inven~ion wa~ reported by the present applicants in a paper by Kokryakov, V.N. et al. FE8S (1993) 337:231-236 (July issue~. A later publication of this group described the presence of a new protegrin, whose sequen~e, and that of its precu:rsor, was deduced from its isolated cDNA clone. Zhao, C et: al, FEB$ Letters (1994) 346:285-288. An additio~al paper disclo~3ing cationic peptides from porcine neutrophils was published by Mirgorodskaya, O.A. et al. FEBS (1993) 330:3:39-342 (September issue). Storici, P. et al. Biochem Bioph~s Res Comm (1993) 196:1363-1367, report the recovery of a DNA sequence which encodes a pig leukocyte antim:icrobial peptide with a cathelin-like prosequence. The pept:ide is reported to be one of the protegrins disclosed hereinbelow. Additional publications related to protegrins are Harwig, S.S.L., et al. J. Peptide Sci. (1995) in press;
and Zhao, C., et al. FEBS-MS MB-283 (1995) in press.
The protegrins of the invention have also been found to bincll:o endotoxins -- i.e., the lipopolysaccharide (LPS) COmE~0~3itionS derived from gram-negative bacteria which are believed responsible for gram-negative sepsis. This type of sep~3i~3 is an extremely common condition and is often fatal.
Others have attempted to design and study proteins which bincl].PS/endotoxin, and illustrative reports of these attempts appear in Rustici, A. et al . Science (1993) 259:361-364i Matsuzaki, K. et al. Biochemistrv (1993) CA 0222247~ 1997-11-26 W 096t37508 PCTrUS96/07594 32:11704-11710; Hoess, A. et al. EMB0 J (1993) 12:3351-3356;
and Elsbach, P. et al . Current O~inion in ImmunoloqY (1993) 5:~03-107. The protegrins of the present invention provide additional compounds which are capable of inactivating of LPS and ameliorating its effects.
In addition to the foregoing, the protegrins of the invention are effective in inhibiting the growth of organisms that are associated with sexually transmitted diseases. It is estimated that 14 million people world-wide are infected with HIV and that millions of women sustain pelvic inflammatory disease each year. Chlamydia trc~chomati~ and Neis~eria gonorr~oeae cause over half of this inflammatory disease although E. coli, Mycoplasma hQminig and other infectious microorganisms can also be re~ponsible. Pathogens include viral, bacterial, fungal and protozoan pathogens. It is especially important that the antibiotics used to combat these infections be effective under physiological conditions. The protegrins of the present invention offer these properties.
Disclosure of the Invention In one embodiment, the invention is directed to peptides of 16-18 amino acid residues characterized by four invariant cysteines and either by a characteristic pattern of basic and hydrophobic amino acids and/or being isolatable from ~n; m~l leukocytes using the method of the invention.
In a second embodiment, the invention is directed to the above peptides wherein 1-4 of these cysteines is replaced by a hydrophobic or small amino acid. All of these peptides can be produced synthetically and ~ome can be produced recombinantly or can be isolated from their native sources and purified for use as preservatives or in pharmaceutical compositions in treating or preventing infection in ~n;m~l s.
Alternatively, the peptides can be formulated into compositions which can be applied to plants to protect them against viral or microbial infection. In still another approach, the DNA encoding the peptides can be expressed in situ, in ~n;~l S or preferably in plants, to combat CA 0222247~ 1997-11-26 W 096~7'iO~ PCTAUSgC~7S94 -- 5 infections. The peptides are also useful as st~n~ds in antimicrobia] assays and in binding endotoxins.
~ccordingly, in one aspect, the invention is directed to a purified and isolated or recombinantly produced compound of the formula Al-A2-.~3-A4-A5-C6-A7-C7-Ag-Alo-All-Al2-cl3-Al4-cl5-Al6-(Al7-Al8) (1) and the N-terminal acylated and/or C-terminal amidated or esterified forms thereof, which is either in the optionally -~;H ~tabilized linear or in a cystine-bridged forrn wherein Al i~ a basic amino acid;
each of A2 and A3 is independently a small amino acid;
each of A5, A7, A14 iS independently a hydrophobic amino acicl;
i~ is a basic or a small amino acid;
each of Ag, Al2 and Al6 is independently a basic, a hydrophobic, a neutral/polar or a small amino acid;
each of Alo and Al1 is independently a basic, a neu~ral/polar, a hydrophobic or a small amino acid or is pro]ine;
i~17 is n~t present or, if present, is a basic, a neut:r~l/polar, a hydrophobic or a small amino acid;
i~18 is not present or, if present, is a basic, a hydrol?hobic, a neutral/polar or a small amino acid, or a modified form of Formula (1) and the N-terminal acy].ated and/or C-terminal amidated or esterified forms thereof wherein at lea~t one of the 4 cysteines is independently replaced by a hydrophobic amino acid or a small amino acid;
with the proviso that the compound of Formula (1) must have a charge of +3 or greater.
:~n still other aspects, the invention is directed to recom}~inant materials useful for the production of the pept:ides of the invention as well as plants or ~n;m~l ~
modi.f:Led to contain expression systems for the production of the~e peptides. The invention is also directed to CA 0222247~ 1997-11-26 W 096/37508 PCTrUS96/07594 pharmaceutical compositions and compositions for application to plants containing the peptides of the invention as active inyredients or compositions which contain expression systems for production of the peptides or for in si tu expression of the nucleotide sequence encoding these peptides. The invention is also directed to methods to prepare the invention peptides synthetically, to antibodies specific for these peptides, and to the use of the peptides as preservatives.
In other aspects, the invention is directed to the use of the compounds of the invention as st~n~A~ds in antimicrobial assays. The compounds many also be used as antimicrobials in solutions useful in eye care, such as contact lens solutions, and in topical or other pharmaceutical compositions for treatment of sexually transmitted diseases (STDs). The invention is also directed to use of the invention compounds as preservatives for foods or other perishables. As the invention peptides can inactivate endotoxin, the invention is also directed to a method to inactivate endotoxins using the ~ ounds of the invention and to treat gram-negative sepsis by taking advantage of this property.

Brief ~escription of the Drawings Figure 1 shows the elution pattern of a concentrate of the ultrafiltrate of porcine leukocytes applied to a Biogel P10 column.
Figure 2 shows the antibacterial activity of the P10 fractions obtained from elution of the column described in Figure 1.
Figure 3 shows an elution pattern obtained when fractions 76-78 from the Biogel P10 column of Figure 1 is applied to HPLC.
Figure 4 shows the antimicrobial activity of the purified porcine protegrins of the invention:
Figure 4a shows antibacterial activity against E. Coli;
Figure 4b shows antibacterial activity against Lieteria monc~cytogenee;

-CA 0222247~ 1997-11-26 W 096/:37'iO8 PC~rAUS~C,'~7~4 ~Figure 4c shows antifungal activity against Candi.da albicans;
]Figure 4d shows antibacterial activity against S.
aureu~.
Figure 4e shows antibacterial activity against K.
pneT~moneAe .
Figure 5 shows the effect of various test conditions on anti.m:icrobial activity:
Figure 5a shows activity against Candida albican~ in 100 ~I NaCl;
Figure 5b ~hows activity against E. Coli in 100 ~M
NaCl.;
Figure 5c shows activity against Candida albicans in 90~ fetal calf serum.
Figure 6 shows the antimicro~ial activity of the linear forms of the protegrins under various test conditions:
Figure 6a shows the activity against E. coli in 10 mM
pho~phate-citrate buffer, pH 6.5;
I~igure 6b shows the activity against E. coli in the same buffer with 100 mM NaCl;
~igure 6c shows the activity against L. monocytogenes in the buffer of Figures 6a-6b;
Figure 6d shows the activity against L. monocytogenes in the same buffer with the addition of 100 mM NaCl;
~igure 6e shows the activity against C. albicans in the presence of 10 mM phosphate; and F~igure 6f shows th.e activity against C. albicans in the presence of 10 mM phosphate plus 100 mM NaCl.
F~igure 7 shows a composite of cDNA encoding the precursors of PG-1, PG-2, PG-3 and PG-4.
Figure 8 shows the nucleotide sequence and the deduced amino acid sequence of the genomic DNA encoding the precutsor protein for the antimicrobial compounds of the invent:ion PG-l, PG-3, and PG-5.
Figure 9 shows the organization of the protegrin genomi.c DNA.

CA 0222247~ 1997-11-26 W O ~6t37S08 PCTrUS~C~

Figure 10 shows the amino acid sequences of the protegrins PG-l to PG-S.
Figures lla-llc show the antimicro~ial activity of synthetically prepared PG-5 as compared to that of synthetically prepared PG-1.
Figures 12a-12d show the effects of various protegrins against various target microbes.
Figure 13 shows a graphical representation of the effects of the kite and bullet forms of PG-l against gram positive bacteria.
Figure 14 shows a graphical representation of the ef~ects of the kite and bullet forms of PG-l against gram negative bacteria.
Figure 15 is a graphical representation of the antimicrobial activity of the snake form of PG-l against gram positive bacteria.
Figure 16 is a graphical representation of the antimicrobial activity of the snake form of PG-1 against gram negative bacteria.
Modes Qf Carrvinq Out the Invention The peptides of the invention are described by the formula:

A1-~2-A3-A4-As-C6-A7-cs-As-Alo-All-Al2-cl3-Al4-cls-Al6-(Al7-Als) (1) and its defined modified forms. Those peptides which occur in nature must be in purified and isolated form or prepared recombinantly.
The designation An in each case represents an amino acid at the specified position in the peptide. As A17 and A18 may or may not be present, the peptides of the invention contain either 16, 17 or 18 amino acids. The positions of the cysteine residues, shown as C in Formula (1), are invariant in the peptides of the invention; however, in the modified forms of the peptides of Formula (1), also included within the scope of the invention, at least one of 1-4 of CA 0222247~ 1997-11-26 W O 96/3750~ PCTlUb~CI'~7a~4 g the~3e cysteines may be replaced by a hydrophobic or small amino acid.
~ rhe amino terminu~ of the peptide may be in the free ami~lo form or may be acylated by a group of the formula RCO--, wherein R represents a hydrocarbyl group of 1-6C. The hydrocarbyl yroup is saturated or unsaturated and is typically, for example r methyl, ethyl, i-propyl, t-butyl, n-pen~yl, cyclohexyl, cycloh~ne-2-yl, h~en~-3-yl, he~ me-4-yl, and the like.
The C-terminus of the peptides of the invention may be in the form cf the underivatized carboxyl group, either as the free acicl or an acceptable salt, such as the potassium, sodium, calcium, magnesium, or other salt of an inorganic ion o:r of an organic ion such as caffeine. The carboxyl terminus may also be derivatized by formation of an ester with an alcohol of the ~ormula ROH, or may be amidated by an amine of the formula NH3, or RNH2, or R2NH, wherein each R is independently hydrocarbyl of 1-6C as defined above.
Amiclated forms of the peptides wherein the C-terminus has the ~ormula C'ONH2 are preferred.
i~8 the peptides of the invention contain substantial numbe:rs of ba,sic amino acids, the peptides of the invention may be supplied in the form of the acid addition salts.
Typical acid addition salts include those of inorganic ions such as chloride, bromi.de, iodide, fluoride or the like, sul~al_e, nitrate, or phosphate, or may be salts of organic anionl3 such as acetate, formate, benzoate and the like. The accepl_ability of each o~ such salts is dependent on the inten~ed use, as is commonly understood.
The peptides of the invention that contain at least two cyst:e:ines may be in straight-chain or cyclic form. The strai~ht-chain forms are convertible to the cyclic forms, and vice ver~a. Methods for forming disulfide bonds to create the cyclic peptides are well known in the art, as are metho~s to reduce disulfides to form the linear compounds.
The l:inear compounds can be stabilized by addition of a suit:able alkylating agent such as iodoacetamide.

CA 0222247~ 1997-11-26 W O 96/37508 PCTrUS96107S94 The cyclic forms are the result of the formation of cystine linkages among all or some of the four invariant cysteine residues. Cyclic forms of the invention include all possible permutations of cystine bond formation; if the cysteines are numbered in order of their occurrence starting at the N-terminus as C6, C8, C13 and C15, these permutations include:
C6 - C8;
C6-C13;
10 C6-Cls;
C8 - C13 i C8-C15;
C13-Cl5;
C6-C8, C13-C15;
C6-C13~ C8-C15; and C6 - C15, C8 - C13 -In the modified forms of the peptides, where 1-4 cysteines are replaced, similar permutations are available when 2-3 cysteines are present.
The native forms of the protegrins contain two cystine bonds are between the cysteine at position 6 and the cysteine at position 15 and the other between the cysteine at position 8 and the cysteine at position 13. Accordingly, in those embodiments having two cystine linkages, the C6-Cl5, C8-Cl3 form is preferred. However, it has been found by the present applicants that forms of the protegrins cont~;n;ng only one cystine linkage are active and easily prepared.
Preferred among embodiments having only one cystine linkage are those represented by C6-Cl5 alone and by C8-C13 alone.
Forms cont~;n;ng a C6-C15 cystine as the only cystine linkage are generally designated "bullet" forms of the protegrins; those wherein the sole cystine is C8-C13 are designated the "kite" forms. The bullet and kite forms can most conveniently be made by replacing the cystines at the positions not to be linked by cystine with a neutral amino acid, preferably a small amino acid such as glycine, serine, alanine or threonine and less preferably a neutral polar amino acid such as asparagine or glutamine. Thus, in CA 0222247~ 1997-11-26 W 096137~jO8 ~CTlub9~v/~4 embodiments of the bullet form each of C8 and Cl3 is independently alanine serine threonine or glycine pre~Eerably both are alanine. Conversely in the kite form C6 c~n~l C1s arle thus replaced.
.i~8 the linearalized forms of the native cyclic peptides have valuable activities even when chemically stabilized to preserve the sulfhydryl form of cysteine for example by reaction with iodoacetamide the compounds of the invention also include linearalized forms which are stabilized with suit:able reayents. A~ defined herein "SH-stabilized" forms of the peptides of the invention contain sulfhydryl groups reac:ted with st~n~Ard reagents to prevent reformation into diswl~Eide linkages.
~n alternative approach to providing linear forms of the protegrins of the invention comprises use of the modif-Led for~ of the peptides where cysteine residues are replaced by amino acids which do not form cystine linkages.
In thiLs instance too all 4 (or at least 3) of the cystines at po~~itions 6 8 13 and 15 are replaced by polar neutral or smzlll amino acids as listed above. It is preferred that all 4 cysteine residue be replaced in order to m; n; m; ze the likelihood of intermolecular bo~;ng.
I'he amino acids denoted by An may be those encoded by the gene or analogs thereof and may also be the D-isomers thereof. One preferred embodiment of the peptides of the invention is that form wherein all of the residues are in the D-configuration thus conferring resistance to protease activity while retaining antimicrobial or antiviral properties. The resulting protegrins are themselves enantiomers oE the native L-amino acid-cont~;n;ng formq.
I'he amino acid notations used herein are conventional and are as fo:Llows:
.

CA 0222247~ l997-ll-26 One-Letter Three-L~tter Amino AcidSymbol Sy~nbol Alanine A Ala Ar~inine R Arg As~,a,_g ~ N Asn Aspartic scid D Asp Cysteine C Cys Glutamine ~ Gln Glutamic acid E Glu Gl~cine G Gly lli~t; " ~; H His I sucine I lle Leucine L Leu Lysine K Lys M~ .e M Met rh~.. t~ e F Phe Praline P Pro Se~ine S Ser Tl~, ~.or. le T Thr Tr~JLOPhan W Trp Ty~osine Y Tyr Valine V Val The amino acids not encoded genetically are abbreviated as indicated in the discussion below.
In the specific peptides shown in the present application, the L-form of any amino acid residue having an optical isomer is intended unless the D-form is expressly indicated by a dagger superscript (t).
The compounds of the invention are peptides which are partially defined in terms of amino acid residues of designated classes. Amino acid residues can be generally subclassified into major subclasses as follows:
Acidic: The residue has a negative charge due to 1088 of H ion at physiological pH and the residue is attracted by aqueous solution so as to seek the surface positions in the conformation of a peptide in which it is contained when the peptide is in aqueous medium at physiological pH.
Basic: The residue has a positive charge due to association with H ion at physiological pH and the residue is attracted by aqueous solution 80 as to seek the surface =

CA 0222247~ l997-ll-26 w O96r~750~ PCT~US96/07S94 positions in the conformation of a peptide in which it i8 conl:ained when the peptide is in aqueous medium at physiological pH.
Hydrophobic: The residues are not charged at physiologica] pH and the residue is repelled by aqueous solution so a8 to seek the inner positions in the confonnation of a peptide in which it i8 contained when the peptide is in aqueous medium.
Neutral~polar: The residues are not charged at physiological pH, but the residue i8 not sufficiently repelled by aqueous solutions so that it would seek inner pos:Ltions in the conformation of a peptide in which it is contained whe.n the peptide is in aqueous medium.
'rhis de~cription also characterizes certain amino acids as "sl~all" since their side ch~;n~ are not sufficiently larc~e, even if polar groups are lacking, to confer hydro]?hobicity. "Small" amino acids are those with four carbons or less when at least one polar group is on the side chain and three carbons or leRs when not.
It is u~derstood, of course, that in a statistical collection of individual residue molecules some molecules wil] be charged, and some not, and there will be an att~-action for or repulsion from an aqueous medium to a greater or lesser extent. To fit the definition of "charqed," a significant percentage (at least approximately 25~) of the individual molecules are charged at phy~;iological pH. The degree of attraction or repulsion re~Lired for classification as polar or nonpolar is arbi.t~rary and, therefore, amino acids specifically cont:emplated by the invention have been classified as one or the olher. Most amino acids not specifically named can be cla~;s:Lfied on the basis of known behavior.
i~mino acid residues can be further subclassified as cycl.ic or noncyclic, and aromatic or nonaromatic, self-explanatory classifications with respect to the side-chain subst-Ltuent groups of the residues, and as small or large.
The residue is considered small if it contains a total of four carbon atoms or less, inclusive of the carboxyl carbon, , CA 0222247~ 1997-11-26 W O 96137508 PCTrUS96107S94 provided an additional polar substituent is present; three or less if not. Small residues are, of course, always nonaromatic.
For the naturally occurring protein amino acids, subclassification according to the foregoing scheme is as follows.

Acidic: Aspartic acid and Glutamic acid;

Basic: Noncyclic: Arginine, Lysine;
Cyclic: Histidine;

Small: Glycine, Serine, Alanine, Threonine;

Polar/larqe: Asparagine, Glut~m; n~;

H~drophobic: Tyrosine, Valine, Isoleucine, Leucine, Methionine, Phenylalanine, Tryptophan.

The gene-encoded secon~ry amino acid proline is a special case due to its known effects on the secondary conformation of peptide ChA; nR ~ and is not, therefore, included in a group. Cysteine residues are also not included in these classifications since their capacity to form disulfide bonds to provide secondary structure is critical in the compounds of the present invention.
Certain commonly encountered amino acids, which are not encoded by the genetic code, include, for example, beta-alanine (beta-Ala), or other omega-amino acids, such as 3-aminopropionic, 2,3-~1~m;nopropionic (2,3-diaP), 4-aminobutyric and so forth, alpha-aminisobutyric acid (Aib), sarcosine (Sar), ornithine (Orn), citrulline (Cit), t-butylalanine (t-BuA), t-butylglycine (t-BuG), N-methylisoleucine (N-MeIle), phenylglycine (Phg), and cyclohexylalanine (Cha), norleucine (Nle), 2-naphthylalanine (2-Nal); 1~2~3~4-tetrahydroisoguinoline-3-carboxylic acid (Tic); ~-2-thienylalanine (Thi); methionine sulfoxide (MSO);

CA 0222247~ l997-ll-26 W O 96/37508 PCT~US96/07594 and homoarginine (Har)~ These also fall conveniently into parl-icular categories.
Based on the above definitions, Sar, bet:a-Ala, 2,3-diaP and Aib are small;
t-BuA, t:-BuG, N-MeIle, Nle, Mvl, Cha, Phg, Nal, Thi and Tic are hydrophobic;
Orn and Har are basici Cit, Acetyl Lys, and MSO are neutral/polar.
The various omega amino acids are classified according to size as ~mall (beta Ala and 3-aminopropionic) or a~ large and hydropho~ic (all others).
Other amino acid substitutions of those encoded in the gene ~an al~o be included in peptide compounds within the scope of the invention and can be classified within this general sche~le according to their structure.
In all of the peptides of the invention, one or more amide linkages (-CO-NH-) may optionally be replaced with anot:h~r linkage which is an isostere such as -CH2NH-, -CH2S-, -CH~CH2, -CH=CH- (cis and trans), -COCH2-, -CH(OH)CH2- and -CH~!SO-. This replacement can be made by methods known in the art. The following references describe preparation of pept:ide analogs which include these alternative-linking moieties: Spatola, A.F., Veqa Data (March 1983), Vol. 1, Issue 3, "Peptide Backbone Modifications" (general re~iew);
Spat:ola, A.F., in 'l~he~;stry and Biochemistry of Amino Acids Pept:ides and Proteins, 1I B. Weinstein, eds., Marcel Dekker, New York, p. 267 (1983) (general review); Morley, J.S., Trends Pharm Sci (1980) pp. 463-468 (general review);
Hud~~on, D., et al., Int J Pept Prot Res (1979) 14:177-185 (-CH2~H-, -CH2CH2-); Spatola, A.F., et al., Life Sci (1986) 38:12~a3-1249 (-CH2-S); Hann, M.M., J Chem Soc Perkin Trans I
(1982~ 307-314 (-CH-CH-, cis and trans); Almquist, R.G., et al., ~J Med Chem (1980) 23:1392-1398 (-COCH2-); Jennings-Whit:e, C., et al., Tetrahedron Lett (1982) 23:2533 (-COCH2-); Szelke, M., et al., European Application EP 45665 (1982,l CA:97:39405 (1982) (-CH(OH)CH2-); Holladay, M.W., et al., Tetrahedron Lett (1983) 24:4401-4404 (-C(OH)CH2-); and Hruby, V.J., Life Sci (1982) 31:189-199 (-CH2-S-).

CA 0222247~ 1997-11-26 W 096/37508 PCTrUS96/07S94 The compounds of Formula (1) are generally defined as Al A2-A3-A4-A5-C6-A7-c7-Ag-Alo-All-Al2-cl3-Al4-cl5-Al6-(A17-A18) (1) and the N-terminal acylated and/or C-terminal amidated or esterified forms thereof, which is either in the optionally -SH stabilized linear or in a cystine-bridged form wherein A1 i8 a basic amino acid;
each of A2 and A3 i5 independently a small amino acid;
each of A5, A7, A14 is independently a hydrophobic amino acld;
A4 is a basic or a small amino acid;
each of Ag, Al2 and A16 is independently a basic, a hydrophobic, a neutral/polar or a small amino acid;
each of A1o and A11 is independently a basic, a neutral/polar, a hydrophobic or a small amino acid or is proline;
A17 is not present or, if present, is a basic, a neutral/polar, a hydrophobic or a small amino acid;
A18 is not present or, if present, is a basic, a hydrophobic, a neutral/polar or a small amino acid, or a modified form of Formula (1) and the N-terminal acylated and/or C-terminal amidated or esterified forms thereof wherein at least one of the 4 cysteines is independently replaced by a hydrophobic amino acid or a small amino acid;
with the proviso that the compound of Formula (1) must have a charge of +3 or greater.
In preferred embodiments of the compounds of the invention, each of A1 and Ag is independently selected from the group consisting of R, K and Har; more preferably, both A1 and Ag are R.
In another class of preferred embodiments, each of A2 and A3 is independently selected from the group consisting of G, A, S and T; more preferably, A2 and A3 are G.

CA 0222247~ l997-ll-26 W 096/37~08 PCTAUS9G~ 4 ~ n another s3et of preferred embodiments, A4 is selected from ~he group consisting of R, K, Har, G, A, S and T; more pref:e~eably, A4 i8 R or G.
:Cn another set of preferred embodiments, each of A5, A14 and A~6 is independently selected independently from the group consisting of I, v, L, Nle and F; preferably I, V, L
and F
Xn another set of preferred embodiments, each of A7 and Al2 is independently selected from the group consisting of I, V, ~,, W, Y and F; preferably A7 is Y and A12 is I or F.
In another set of preferred embodiments, Alo is R, G or P.
~:n another set of preferred embodiments, All is R or W.
~17, when present, is preferably G, A, S or T, most preferably G;
~ 18, when present, is preferably R, K or Har, most prefe~ably R.
~ ?~8 descxibed above, the compounds of Formula (1) are either in cyclic or noncyclic (linearalized) form or may be modifi.ed wherein 1-4 o~ the cysteines is replaced by a small amino acid rel3idue or a hydrophobic residue or a nonpolar large amino acid residue. If the linearalized forms of the compound of Formula (1) are prepared, or if linearalized forms of tho~e modified peptides which contain at least two cysteines are prepared, it is preferred that the sulfhydryl groups' be stabilized by addition of a suitable reagent.
Preferred ~mho~;m~nts for the hydrophobic amino acid to replace cyste:ine residues are I, V, L and NLe, preferably I, V or ~,. Preferred small amino acids to replace the cysteine residues include G, A, S and T, most preferably G.
Pref~erred larqe polar amino acids are N and Q.
In an alt:ernative embo~;ment, the peptides of the invention are defined as described by Formula (1), but wherein the definitions of An in each case are determined by the isolatabi].ity of the peptide from An;mAl leukocytes by the invention method. The invention method comprises the steps of provi.ding an ultrafiltrate of a lysate of An;mAl leukocytes and isolating peptides of 16-18 amino acids.

CA 0222247~ l997-ll-26 W 096137508 PCTrU~9G~'~/a~4 These peptides can further be defined by the ability of DNA
encoding them to hybridize under stringent conditions to DNA
encoding the peptides exemplified as PG-l, PG-2, PG-3, PG-4 and PG-5 herein.
Particularly preferred compounds of the in~ention are:

Unmodified forms PG-1: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-G-R
PG-2: R-G-G-R-L-C-Y-C-R-R-R-F-C-I-C-V
PG-3: R-G-G-G-L-C-Y-C-R-R-R-F-C-V-C-V-G-R
PG-4: R-G-G-R-L-C-Y-C-R-G-W-I-C-F-C-V-G-R
PG-5: R-G-G-R-L-C-Y-C-R-P-R-F-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V
K-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V
R-G-G-Har-L-C-Y-C-R-R-R-F-C-V-C-V
R-G-G-Har-L-C-Y-C-Har-R-R-F-C-V-C-V-G-R
R-G-G-R-V-C-Y-C-R-Har-R-F-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-K-K-W-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-Har-R-Y-C-V-C-V-G-R
R-G-S-G-L-C-Y-C-R-R-K-W-C-V-C-V-G-R
R-A-T-R-I-C-F-C-R-R-R-F-C-V-C-V-G-R
R-G-G-K-V-C-Y-C-R-Har-R-F-C-V-C-V-G-R
R-A-T-R-I-C-F-C-Rt-R-R-F-C-V-C-V-G-Rt R-G-G-K-V-C-Y-C-R-Hart-R-F-C-V-C-V-G-R
PG-1: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-G-R (all t) PG-2: R-G-G-R-L-C-Y-C-R-R-R-F-C-I-C-V (all t) PG-3: R-G-G-G-L-C-Y-C-R-R-R-F-C-V-C-V-G-R (all t) PG-4: R-G-G-R-L-C-Y-C-R-G-W-I-C-F-C-V-G-R (all t) PG-5: R-G-G-R-L-C-Y-C-R-P-R-F-C-V-C-V-G-R
PC-39: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-R
PC-41: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-G
PC-100: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-Y
PC-101: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-T
PC-102: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-A
PC-103: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-L
PC-104: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-I
PC-105: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-F

CA 0222247~ 1997-11-26 W 096S;~7~,0~ PCT~US~ 7a~4 PC-1.06: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-W
PC-1.0~3: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-R
R-G-G-R-L-C-W-C-R-R-R-F-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-W-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-W-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-W-G-R
IB-247: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-G-R-OH
IB-249: R-G-G-G-L-C-Y-C-R-R-R-F-C-V-C-V-G-R-OH
IB-223: R-G-G-G-L-C-Y-C-R-R-G-F-C-V-C-F-G-R
IB-224: R-G-G-G-L-C-Y-C-R-R-P-F-C-V-C-V-G-R
IB-324: R-G-G-G-L-C-Y-C-R-P-R-F-C-V-C-V-G-R-OH
IB-341: R-G-G-R-L-C-Y-C-R-X-R-F-C-V-C-V-G-R-OH (X=NMeG) IB-342: R-G-G-R-L-C-Y-C-R-X-R-F-C-V-C-V-G-R (X=NMeG) IB-384: R-G-G-R-L-C-Y-C-X-G-R-F-C-V-C-V-G-R (X=Cit) IB-39~: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V-G-R
IB-395~: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V-G-R-OH
IB-21~,: R-G-G-G-L-C-Y-C-F-P-K-F-C-V-C-V-G-R
IB-3451: R-G-G-R-L-C-Y-C-R-X-R-Cha-C-V-C-W-G-R (X=NMeG) IB-35~: R-G-G-R-W-C-V-C-R-X-R-Cha-C-Y-C-V-G-R (X=NMeG) IB-394': R-G-G-R-W-C-V-C-R-G-R-Cha-C-Y-C-V-G-R
IB-416;: R-G-G-R-L-C-Y-C-R-R-R-F-C-NMeV-C-V-G-R
IB-40CI: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V
IB-401.: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V-OH
both t,he linear and mono- and bicyclic forms thereof, and including the N-terminal acylated and C-terminal amidated forms;

Modifi.ed form~3 R-G-G-R-L-V-Y-C-R-R-R-F-C-V-C-V-G-R
R-G-G--R-L-G-Y-C-R-R-R-F-C-I-C-V
R-G-G--G-L-C-Y-G-R-R-R-F-C-V-C-V-G-R
R-G-G~R-L-G-Y-G-R-R-R-F-G-V-C-V
K-G-G R-L-V-Y-V-R-R-R-F-I-V-C-V
R-G-G~Har-L-C-Y-C-R-R-R-F-C-V-G-V
R-G-G--Har-L-C-Y-C-Har-R-R-F-C-V-L-V-G-R
R-G-G--R-V-C-Y-V-R-Har-R-F-L-V-G-V-G-R

CA 0222247~ l997-ll-26 W 096~7S08 PCTrUS96/07S94 R-G-G-R-L-C-Y-S-R-K-K-W-C-V-S-V-G-R
R-G-G-R-L-C-Y-C-R-Har-R-Y-S-V-V-V-G-R
R-G-S-G-L-S-Y-C-R-R-K-W-G-V-C-V-G-R
R-A-T-R-I-S-F-S-R-R-R-F-S-V-S-V-G-R
R-G-G-K-V-C-Y-G-R-Har-R-F-S-V-C-V-G-R
R-A-T-R-I-V-F-C-Rt-R-R-F-G-V-C-V-G-Rt R-G-G-K-V-C-Y-L-R-Hart-R-F-L-V-C-V-G-R
R-G-G-R-I-C-F-L-R-P-R-I-G-V-C-V-G-R
PC-49: R-G-G-R-L-C-W-A-R-R-R-F-A-V-C-V-G-R
PC 50: R-G-G-R-L-C-Y-A-R-R-R-W-A-V-C-V-G-R
PC 52: R-G-G-R-L-A-W-C-R-R-R-F-C-V-A-V-G-R
PC 53: R-G-G-R-L-A-Y-C-R-R-R-F-C-V-A-W-G-R
PC 55: R-G-G-R-L-A-W-A-R-R-R-F-A-V-A-V-G-R
PC~56: R-G-G-R-L-A-Y-A-R-R-R-W-A-V-A-V-G-R
PC-57: R-G-G-R-L-A-Y-A-R-R-R-F-A-V-A-W-G-R
IB -214: R-G-G-G-L-C-Y-A-R-G-W-I-A-F-C-V-G-R
IB-216: R-G-G-G-L-C-Y-A-R-G-F-I-A-V-C-F-G-R
IB-225: R-G-G-G-L-C-Y-A-R-P-R-F-A-V-C-V-G-R
IB-226: R-G-G-G-L-C-Y-T-R-P-R-F-T-V-C-V-G-R
IB-227: R-G-G-G-L-C-Y-A-R-K-G-F-A-V-C-V-G-R
IB-288: R-G-G-R-L-C-Y-A-R-R-R-F-A-V-C-V-G-R-OH
IB-289: R-G-G-R-L-C-Y-A-R-R-R-F-A-V-C-V-G-R

both the linear and cyclic (where possible) forms thereof, and including the N-terminal acylated and C-terminal amidated forms.
Particularly preferred are compounds wherein a single cystine bond is formed between C6 and Cl5 or between C8 and Cl3 wherein four compounds having a cystine bond between C8 and Cl3 each of C6 and C15 is independently replaced by "X"
wherein X is a hydrophobic, a small, or a large polar amino acid. Similarly, where the single cystine bond is between C8 and C13, each of C6 and Cl5 is independently replaced by X
as defined above. Also preferred are the "snake" forms of the compounds of the invention where all 4 cysteines are replaced by X as defined above. Particularly preferred embodiments of these compounds of the invention include:

CA 02222475 l997-ll-26 W 0961375~8 PCTrUS96/07S94 Kite form-l R-G-G-R-L-X-Y-C-R
R
R
R-G-V-X-V-C-F
10 Kit(o form-2 R-G-G-R-L-X-Y-C-R
\

R
R-G-V-X-I-C-F
Kite form-3 R-G-G-G-L-X-Y-C-R

R

R
R-G-V-X-V-C-F
K;te form-4 R-G-G-R-L-X-Y-C-R
W
G
R-G-V-X-F-C-I
Kite form-5 R-G-G-R-L-X-Y-C-R
p R
R-G-V-X-V-C-F

Bullet form-l R-G-G-R-L-C-Y-X-R
R
R
R-G-V-C-V-X-F

CA 0222247~ 1997-11-26 W 09~6/37508 PCT~US96/07594 Bullet form-2 R-G-G-R-L-C-Y-X-R
R
R
R-G-V-C-I-X-F
Bullet form-3 R-G-G-G-L-C-Y-X-R
~RR

R-G-V-C-V-X-F
Bu].let form-4 R-G-G-R-L-C-Y-X-R
W
G
R-G-V-C-F-X-I
~ullet form-5 R-G-G-R-L-C-Y-X-R
\

R
R-G-V-C-V-X-F

Snake form-1: R-G-G-R-L-X-Y-X-R-R-R-F-X-V-X-V-G-R
Snake form-2: R-G-G-R-L-X-Y-X-R-R-R-F-X-I-X-V
Snake form-3: R-G-G-G-L-X-Y-X-R-R-R-F-X-V-X-V-G-R
.~n~ke form-4: R-G-G-R-X-L-X-Y-R-G-W-I-X-F-X-V-G-R
Snake form-5: R-G-G-R-L-X-Y-X-R-R-R-F-X-V-X-V-G-R
wherein X is as defined above.
Particularly preferred embodiments of X are those wherein X is a small amino acid, especially S and A, especially A.

PreParation of the Invention Compounds The invention compounds, often designated herein "protegrins" are essentially peptide backbones which may be modified at the N- or C-terminus and also may contain one or CA 0222247~ 1997-11-26 W O 961~37~~8 PCT~US~6/07S94 two cystine ~1isulfide linkages. The peptides may first be synthesized :in noncyclized form. These peptides may then be converted to the cyclic peptides if desired by st~n~d methods of cystine bond formation. As applied to the protegrins herein, "cyclic forms" refers to those forms whi,-h contain cyclic portions by virtue of the formation of disulfide liIlkages between cysteine residues in the peptide.
If lthe straight-chain forms are preferred, it is preferable to ~3tabilize the sulfhydryl groups for any peptides of the invention which contain two or more cysteine residues.
St~n~rd methods of synthesis of peptide~ the size of pro1e~yrins a~e known. Most co~only used currently are sol:id phase ~~ynthesis techniques; indeed, automated equipment for systematically constructing peptide ch~-n.~ can be purchased. Solution phase synthesis can also be used but is co~siderably less convenient. When synthesized using these st~n~r~d techniq~Les, amino acids not encoded by the gene ;3Lnd D-en~antiomers can be employed in the synthec~is.
Thuc3, one very practical way to obtain the compounds of the inven1_ion is to employ these st~n~d chemical synthesis tec~m:iques .
:Cn addition to providing the peptide backbone, the N-and/~or C-terminus can be derivatized, again using con~entional chemical techniques. The compounds of the invent:ion may optionally contain an acyl group, preferably an acetyl group at the amino ter~minus. Methods for acety~ating or, more generally, acylating, the free amino group at the N-terminus are generally known in the art; in addition, the N-terminal amino acid may be supplied in the synthesis in acylated form.
~ t the carboxy terminus, the carboxyl group may, of course, be present in the form of a salt; in the case of pharmaceutical compositions this will be a pharmaceutically accept:able salt. Suitable salts include those formed with inorgaLnic ion3 such as NH4+, Na+, K+, Mg++, Ca++, and the like as well as salts formed with organic cations such as those of caffeine and other highly substituted ~ml neR ~ The carbo~ terminus may also be esterified using alcohols o~

CA 0222247~ 1997-11-26 W 096/37508 PCTrUS9''~7S94 the formula ROH wherein R is hydrocarbyl (1-6C) as defined above. Similarly, the carboxy terminus may be amidated 80 as to have the formula -CONH2, -CONHR, or -CONR2, wherein each R is independently hydrocarbyl (1-6C) as herein defined. Techniques for esterification and amidation as well as neutralizing in the presence of base to form ~alts are all standard organic chemical techniques.
If the peptides of the invention are prepared under physiological conditions, the side-chain amino groups of the basic amino acids will be in the form of the relevant acid addition salts.
Formation of disulfide linkages, if desired, is conducted in the presence of mild oxidizing agents.
Chemical oxidizing agents may be used, or the compounds may simply be exposed to the oxygen of the air to effect these linkages. Various methods are known in the art. Processes useful for disulfide bond formation have been described by Tam, J.P. et al., Svnthesis (1979) 955-957; Stewart, J.M. et al, "Solid Phase Peptide Synthesis" 2d Ed. Pierce Chemical Co~r~ny Rockford, IL (1984); Ahmed A.K. et al., J Biol Chem (1975) ~Q:8477-8482 and Pennington M.W. et al., Pe~tides 12~Q, E- Giralt et al., ESCOM Leiden, The Netherlands (1991) 164-166. An additional alternative is described by Kamber, B. et al., Helv Chim Acta (1980) 63:899-915. A method conducted on solid supports is described by Albericio Int J
Pe~t Protein Res (1985) 26:92-97.
A particularly preferred method is solution oxidation using molecular oxygen. This method has been used by the inventors herein to refold synthetic PG-l, PG-3 in its amide or acid forms, enantioPG-l and the two unisulfide PG-1 compounds (C6-Cl5 and C8-Cl3). Recoveries are as high as 30~.
If the peptide backbone is comprised entirely of gene-encoded amino acids, or if some portion of it is so composed, the peptide or the relevant portion may also be synthesized using recombinant DNA techniques. The DNA
encoding the peptides of the invention may itself be synthesized using commercially available equipment; codon CA 0222247~ 1997-11-26 W o96J37slDs PCTAUS96/07S94 choice can be integrated into the synthesis depending on the nat~lre of the host. Alternatively, although less conve3lient, the DNA can be obtained, at least initially, by scree3~Ling a cDNA library prepared from porcine leukocytes S using probes or PCR primers based on the sequences of the prot:egrins described herein. This results in recovery of the naLturally occurring sequence encoding the protegrins of the invention. Obtention of this native sequence is significant for purposes other than the synthesis of the prot:e~rins per se; the availability of the naturally occurring sequences provides a useful probe to obtain corr-ef3ponding DNA encoding protegrins of other species.
Thuf~, cDNA libraries, for example, of leukocytes derived fro~lc~ther ~n;m~l S can be screened using the native DNA, pre~erably under conditions of high stringency. High stringency is as defined by Maniatis, et al. Molecular oniIlq: a LaboratorY Manual 2nd Ed, Cold Spring Harbor ~aborcltory Press (1989), the relevant portions of which are incorporated herein by reference. This procedure also per~lit:s recovery of allelic variants of these peptides from the same species.
Alternatively, the protegrins can be prepared by isolat:ion from leukocytes of a desired species using techniques similar to those disclosed herein for the isolat:ion of porcine protegrins. In general, these techni.ques involve preparing a lysate of a leukocyte preparation, ultrafiltering the supernatant of the clarified lysate and recovering the ultrafiltrate. The ultrafiltrate is then subje,cted to chromatographic separation. The location of fragments having antimicrobial and antiviral activity corresponding to protegrins can be assessed using criteria of molecular weight and assaying the fractions for the desired activities as described herein. The native for~s of these peptides are believed to be the cyclic forms;
if de-f~ired, the linearalized forms can be prepared by treating the peptides with reducing agents and stabilizing the suLlfhydryL groups that result.

CA 0222247~ 1997-11-26 W 096/37508 PCT~US96/07S94 Isolated and recombinantly produced forms of the protegrins may require subsequent derivatization to modify the N- and/or C-terminus and, depending on the isolation procedure, to effect the formation of cystine ~onds as de~cribed hereinabove. Dep~;n~ on the host organism used for recombinant production and the ~n;m~l source from which the protein is isolated, some or all of these conversions may already have been effected.
For recombinant production, the DNA encoding the protegrins of the invention is included in an expression system which places these coding sequences under control of a &uitable promoter and other control sequences compatible with an intended host cell. Types of host cells available span almost the entire range of the plant and An~m~l kingdoms. Thus, the protegrins of the invention could be produced in bacteria or yeast (to the extent that they can be produced in a nontoxic or refractile form or utilize resistant strains) as well as in animal cells, insect cells and plant cells. Indeed, modified plant cells can be used to regenerate plants cont~;n;ng the relevant expression systems so that the resulting transgenic plant is capable of self protection vis-à-vis these infective agents.
The protegrins of the invention can be produced in a form that will result in their secretion from the host cell by fusing to the DNA encoding the protegrin, a DNA encoding a suitable signal peptide, or may be produced intracellularly. They may also be produced as fusion proteins with additional amino acid sequence which may or may not need to be subsequently Le...oved prior to the use of the~e compounds as antimicrobials or antivirals.
Thus, the protegrins of the invention can be produced in a variety of modalities including chemical synthesis, recombinant production, isolation from natural sources, or some combination of these techniques.
Those members of the protegrin class which occur naturally are supplied in purified and isolated form. By "purified and isolated" is meant free from the environment in which the peptide normally occurs (in the case of such CA 0222247~ 1997-11-26 W 096137'~-)08 PCT~US9Clv~

naturally occurring peptides) and in a form where it can be use/~ practically. Thu~, "purified and isolated" form means thalt the pept:ide is substantially pure, i.e., more than 90~
pure, preferably more than 95~ pure and more pre~erably more tha~l 99~ pure or is in a completely different context such as l_hat of a pharmaceutical preparation.

Ant:ibodies .~ntibodi.es to the protegrins of the invention may also be produced using ,standard ;m~l-nological techniques for production of polyclonal antisera and, if desired, immortalizing the antibody-producing cells of the ;m~l~n; zed host ~or sources o~ monoclonal antibody production.
Tec~mi~ues for producing antibodies to any substance of interest are well known. It may be nece~sary to ~nh~nce the ;~mllnogenicity of the substance, particularly as here, where the material is only a short peptide, by coupling the hapten to a carrier. Suitable carriers for this purpose include sub~;tances which do not themselves produce an ;mmnn~
respollse in the m~m~l to be ~m; n; stered the hapten-carrier conjlugate. Co.~ carriers used include keyhole limpet hemocyanin (KLH), diphtheria toxoid, serum albumin, and the viral coat protein of rotavirus, VP6. Coupling of the hapten to the carrier is effected by standard techniques such clS contacting the carrier with the peptide in the pre~ence of a dehydrating agent such as dicyrclohexylcarbodiimide or through the use of linkers such a~ those available through Pierce Chemical Company, Chicago, I~.
~'he protegrins of the invention in ;m~llnogenic form are then i.njected into a suitable m~mm~l ian host and antibody titer~; in the serum are monitored. It should be noted, however, that some forms of the protegrins require modification before they are able to raise antibodies, due to their resistance to antigen processing. For example, the native form of PG-1, containing two cystine bridges is non;mmllnogeniC when ~m;n;stered without coupling to a larger carrier and was a poor imml~nogen even in the presence CA 0222247~ 1997-11-26 W O 96/37508 PCTrUS96/07S94 of potent adjuvants and when coupled through glutaraldehyde or to K~H. Applicants believe this to be due to its resistance to attack by leukocyte serine proteases (human PMN elastase and cathepsin G) as well as to attack by an aspartic protease (pepsin) that resembles several macrophage cathepsins The lack of ;mmllnogenicity may therefore result from resistance to processing to a linear form that can fit in the antigen-presenting pocket of the presenting cell.
Immunogenecity of these forms of the protegrins can be enhanced by cleaving the disulfide bonds.
Polyclonal antisera may be harvested when titers are sufficiently high. Alternatively, antibody-producing cells of the host such as spleen cells or peripheral blood lymphocytes may be harvested and immortalized. The immortalized cells are then cloned as individual colonies an~ screened for the production of the desired monoclonal antibodies.
The antibodies of the invention are, of course, useful in ;mmllnoassays for determining the amount or presence of the protegrins. Such assays are essential in quality controlled production of compositions cont~;n;ng the protegrins of the invention. In addition, the antibodies can be used to assess the efficacy of recombinant production of the protegrins, as well as screening expression libraries for the presence of protegrin encoding genes.

Compositions Containinq the Proteqrins and Methods of Use The protegrins of the invention are effective in inactivating a wide range of microbial and viral targets, including gram-positive and gram-negative bacteria, yeast, protozoa and certain strains of virus. Accordingly, they can be used in disinfectant compositions and as preservatives for materials such as foodstuffs, cosmetics, medicaments, or other materials containing nutrients for oryanisms. For use in such contexts, the protegrins are supplied either as a single protegrin, in admixture with several other protegrins, or in admixture with additional antimicrobial agents. In general, as these are CA 0222247~ 1997-11-26 W 096~.S~S~0~ PCT~US96/07S94 prese~atives in this context, they are usually present in relatLvely low amounts, of less than 5~, by weight of the total composition, more preferably less than 1~, still more prefierably less than o.l~.
lrhe peptides of the invention are also useful as stanLdards in antimicrobial assays and in assays for deternnination of capability of test compounds to bind to endotoxins such as lipopolysaccharides.
~or use as antimicrobials or antivirals for treatment of ~nl'm~l subjects, the protegrins of the invention can be formu]ated as pharmaceutical or veterinary compositions.
Depencling on the subject to be treated, the mode of admini.~tratio;n, and the type of treatment desired -- e.g., prevention, prophylaxis, therapy; the protegrins are form~u]ated in ways consonant with these parameters. A
summlary of such techniques is found in Remington's Pharmaceutical Sciences, latest edition, Mack Publishing Co., E~aston, PA.
~'he prot,egrins are particularly attractive as an active ingreciients pharmaceutical compositions useful in treatment of se~ally transmitted diseases, including those caused by Chlam~dia trachomatis, TL~v lema pallidum, Nei Beria gonor2-hoeae, Trichomn~ vaginalis, Herpes simplex type 2 and H~V. Topical formulations are preferred and include creams, salves, oils, powders, gels and the like. Suitable topical excipient are well known in the art and can be adapted for particular uses by those of ordinary skill.
~ n genexal, for use in treatment or prophylaxis of STDs, the protegrins of the invention may be used alone or in combination with other antibiotics such as erythromycin, tetracycline, macrolides, for example azithromycin and the cephalosporin~3. Depending on the mode of administration, the protegrin~3 will be formulated into suitable compositions to pe~mit fac:ile delivery to the affected areas. The protegrins may be used in forms containing one or two disulfiide bri~ges or may be in linear form. In addition, use of the enantiomeric forms containing all D-amino acids may confer advantages such as resistance to those proteases, CA 0222247~ 1997-11-26 W O 96/37~08 PCTrUS96/07S94 su~h as trypsin and chymotrypsin, to which the protegrins COllt~; n;ng L-amino acids are less resistant.
The protegrins of the invention can be A~m;n;stered singly or as mixtures of several protegrins or in combination with other pharmaceutically active com~onents.
The formulations may be prepared in a m~nn~r suitable for sy~temic admini~tration or topical or local administration.
Sy~temic formulations include those designed for injection (e.g., intramuscular, intravenous or subcutaneous injection) or may be prepared for transdermal, transmucosal, or oral administration. The formulation will generally include a diluent as well as, in some cases, adjuvants, buffers, preservatives and the like. The protegrins can be administered also in liposomal compositions or as microemulsions.
If administration is to be oral, the protegrins of the invention must be protected from degradation in the stomach using a suitable enteric coating. This may be avoided to some extent by utilizing amino acids in the D-configuration, thus providing resistance to protease. However, the peptide is still susceptible to hydrolysis due to the acidic conditions of the stomach; thus, some degree of enteric coating may still be required.
As described in the examples below, the peptides of the invention retain their activity against microbes in the context of borate solutions that are co~monly used in eye care products. It has also been shown that when tested for antimicrobial activity against E. coli in the presence and absence of lysozyme in borate buffered saline, that the presence of lysozyme ~nh~nced the effectiveness of PG-3.
Thi~ effect was more pronounced when the PG-3 was autoclaved and similar patterns were obtained for both the free-acid form and the amide. Accordingly, the protegrins may be used as preservatives in such compositions or as antimicrobials for treatment of eye infections.
It is particularly important that the protegrins retain their activity under physiological conditions including relatively high saline and in the presence of serum. In CA 0222247~ l997-ll-26 W O9611~50X PCTfUS9~/07S94 additiLon, the protegrins are not cytotoxic with respect to the cells of higher organisms. These properties, described herein below in the Examples, make them particularly suitable for in vivo and therapeutic use.
~he protegrins of the invention may also be applied to plan~ts or to their environment to prevent viral- and microbial-induced diseases in these plants. Suitable compo~3itions for this use will typically contain a diluent as ~e]l as a spreading agent or other ancillary agreements beneficial to the plant or to the environment.
~ 'hus, the protegrins of the invention may be used in any context wherein an antimicrobial and/or antiviral action is re~uired. This use may be an entirely in vitro use, or the peptides may be administered to organisms.
~:n addition, the antimicrobial or antiviral activity may be generated in situ by ~m; n; stering an expression system suitable for the production of the protegrins of the invent:ion. Such expression systems can be supplied to plant and An;~Al s~bjects using known techniques. For example, in ~n;ml~ls~ pox-based expression vectors can be used to generate the peptides in ~itu. Similarly, plant cells can be trans~ormed with expression vectors and then regenerated into whole plants which are capable of their own production of the peptides.
~ particularly useful property of the protegrins is their activi~y in the presence of serum. Unlike defensins, protegrins ar(e capable of exerting their antimicrobial effect:s in the presence of serum.
~s showl~ hereinbelow, the protegrins are capable of inactivating lendotoxins derived from gram-negative bacteria -- i.e., lipopolysaccharides (LPS) -- in st~n~rd assays. Accordingly, the protegrins may be used under any circumstances where inactivation of LPS is desired. One such situation is in the treatment or amelioration of gram-negative sepsis.
The protegrins of the invention, therefore, represent apeculiarly u~~eful class of compounds because of the following properties:

CA 0222247~ 1997-11-26 W 096/37508 PCTrUS96/07S94 1) they have an antimicrobial effect with respect to a broad spectrum of target microbial systems, including viruses, including retroviruses, bacteria, fungi, yeast and protozoa.

2) Their antimicrobial activity is effective under physiological conditions - i.e., physiological saline and in the presence of serum.

3) They are not toxic to the cells of higher organisms.

4) They can be prepared in non;mmllnogenic form thus extending the number of species to which they can be administered.

5) They can be prepared in forms which are resistant to certain proteases suggesting they are antimicrobial even in lysosomes.

6) They can be prepared in forms that resist degradation when autoclaved, thus simplifying their preparation as components of pharmaceuticals.
The following examples are intended to illustrate but not to limit the invention.

Exam~le 1 Isolation of PG-l PG-2 and PG-3 Fresh porcine blood was collected into 15-liter vessels corltaining 5~ EDTA in normal saline, pH 7.4 as an anticoagulant (33 ml/liter blood). The blood cells were allowed to sediment for 90 minutes at room temperature and the leukocyte-rich supernatant was removed and centrifuged at 200 x g for 5.7 minutes. The pellets were pooled and su~pended in 0.84~ ~m~o~um chloride to lyse erythrocytes and the resulting leukocytes (70-75~ PMN, 5-10~ eosinophils, 15-25~ lymphocytes and monocytes) were washed in normal saline, re~uRpended in ice-cold 10~ acetic acid at 108/ml, homogenized and stirred overnight at 4~C. The preparation was centrifuged at 25,000 x g for 3 hours at 4~C and the supernatant was lyophilized and weighed.

CA 0222247~ 1997-11-26 W 096J375~8 PCT~US96~07~94 950 mg (dry weight) of lyophilized extract, which cont:a:ined 520 mg protei.n by BCA analysis, was stirred overn:ight at 4~C in 100 ml of 10~ acetic acid and then cent:r:ifuged a.t 25,000 x g for 2 hours. The supernate was ,e"lo~ed and passed by pressure through a 50 ml stirred ultracentrifu.gation cell (Amicon, Danvers, MA) that cont:a:ined a YM-5 filter. The ultrafiltrate (24.5 mg protein by B~) was concentrated to 3 ml by vacuum centrifugation (SpeedVac Con.centrator, Savant Instruments, Hicksville, NY), applied to a 2.5 x 117 cm BioGel P10 column ~Bio-Rad, Herc:u:Les, CA) and eluted at 4~C with 5% acetic acid.
Fraction.s cont~; ni ng 6.6 ml were obt~;ne~. Fractions were assayed by absorption at 280 nm and the elution pattern i5 shown in Figure 1.
i~l iquots (66 ~l) of each fraction were dried by vacuum cent:r:ifugation and resuspended in 6.6 ~l of 0.01~ acetic acicl. Five ~l samples of this concentrate were tested for anti.m:icrobial activity against E. coli ML-35, L. n~o~ocytogenes, strain EGD and C. albicans, strain 820, using radiodiffusion and gel overlay techniques as described by I,ehrer, R.I. et al. J Immunol Meth (l991) 137:167-173.
Brief:Ly, the underlay agars used for all organisms had a final pH of 6.5 and contained 9 mM sodium phosphate/1 mM
sodi.um citrate buffer, 1~ w/v agarose and 0.30 ~g/ml tryptocase soy broth powder (BBL Cockeysville, MD). The unit:s of activity in the radial diffusion assay were mea~~ured as d.escribed; 10 units correspond to a 1 mm diameler clear zone around the sample well. Activities obtailled for the various fractions are shown in Figure 2.
Acti.v:ity was found in a large number of fractions.
The active fractions were further e~mlned by acid-urea PAGE' (AU-PAGE) and SDS PAGE. Results of these analyses showre~ that active anti.microbial peptides of the appropriate molecular weight were present and concentrated in fractions 76-,'8.
Fractions 76-78 from the Biogel P10 column were then pool.ed and chromatographed on a 1 x 25 cm Vydac 218 TP1010 CA 0222247~ 1997-11-26 W 096/37508 PCT~US96/07S94 column with a gradient (buffer A is 0.1~ TFA; buffer B is 0.1~ TFA in acetonitrile) the increase in acetonitrile concentration was 1~ per minute. The results, assessed in terms of absorbance at 280 nm and at 225 nm are shown in Figure 3. The peaks corresponding the three peptides illustrated herein are labeled in the figure. The figure also contains an inset which shows the results of an acid-urea PAGE gel stained with Comassie Blue that contains a starting mixture composed of the pooled fractions and the individual PG species. These are labeled M, 1, 2 and 3 on the inset. The results clearly show the presence of three di~:tinct proteins.
The isolated proteins were subjected to amino acid analysis using three independent methods, and to Edman lS degradation, chymotrypsin digestion, and fast atom bombardment mass spectrometric analysis. The peptides, named "protegrins", are shown to have the amino acid se~uences as follows:
~ RGGRhCYCRRRF~v~v~
PG-2: RGGR~CYCRRRFCICV
PG-3: RGGGLCYCRRRF~K, and are amidated at the C-terminus.
The amidation status of the isolated peptides was established by synthesis of PG-3 both in the free carboxyl and carboxyamidated forms. These synthetic peptides were then compared to isolated PG-3 using AU-PAGE and also using reverse-phase HPLC. In both cases, the native product comigrated with the synthetic amidated form.
The location of the disulfide linkages in the isolated protegrins was also studied using PG-2 as a model. The determination was performed using sequential enzyme digestion (chymotrypsin followed by thermolysin) with direct analysis using LC-ESI-MS on the fragments obtained. The res~lts of these analyses showed that the two intramolecular disulfide bonds were C6-Cl5 and C8-Cl3. With the location of the disulfides in these positions, the protegrin molecules CA 0222247~ l997-ll-26 W 096137508 PCTrU$96/07S94 are likely to exist as anti-parallel ~ sheets similar to the tac]~Lyplesin~ in overall conformation.
The antimicrobial proteins above are present in much lower concentrations in initial extracts than are the rabbit defensins in corresponding crude extracts where the defensins corLstitute more than 15~ of the total protein in rabbit granulocytes. Using the AU-PAGE analytical method on the various ~tages of purification, the peptides are only faintly visible in the crude extracts, whereas corresponding crucle extracts of rabbit granulocytes clearly show the pre~3e~ce of the defensins. The peptides of the invention become clearly evident only after the ultrafiltration step.
~ 3ecause the protegrins whose structures are set forth above show sequence homology to the decapeptide region corre~3ponding to residues 1-10 of rabbit defensin NP-3a in the d~capeptide region at positions 4-13 of PG-3, the prot:ec~rins, and in particular PG-3, may share the property of cLei.ensin N'P-3a in being capable of competitively antagonizing ACTH-mediated steroid synthesis by adrenocytes.
Thi~ property, called "corticostasis", may influence the effect:ivenes~ of the protegrins as antiinfectious agents when employed in vivo.

Exam~le 2 Antimicrobial Activit~
~'he radial diffusion assay in agarose gels described in Exampl.e 1 was also used to test the activity of the purified protegrins. Figures 4a, 4b and 4c show the results again~t three test or~anisms in units described as above. The rabbit defensin (NP-l) and the human defensin (HNP-l) were used aLs controls.
E'igure 4a shows that PG-1 and PG-3 are more effective again~t E. co.li ML-35P than HNP-l and only slightly le~2s effective than NP-l. PG-l and PH-3 were also effective against Liste:ria monocytogenes, strain EGD as shown in Figure 4b. In Figure 4c, PG-l and PG-3 were also shown effective aga.inst Candida albicans. In general, these CA 0222247~ 1997-11-26 W 096/37508 PCTrUS96107S94 peptides are approximately as effective as rabbit defensin NP-1 on a weight basis and are more effective than HNP-1.
In all cases, PG-2 was also effective against the three organisms tested but was not as active as the other two peptides.
In addition to its activity in inhibiting the growth of the above-mentioned organisms, the PG-1 of the invention has been shown directly to inhibit the growth of Staphylococcu~
aureus (see Figure 4d) and K. pne~moneAe 270 (Figure 4e).
HNP-1 used as a control was less effective against S. aureus and almost entirely ineffective against K. pne~m~ne~e.
The protegrins of the invention have also been tested against various other organisms and show broad spectrum activity. In addition to their effectiveness in inhibiting the growth of or infection by microorganisms associated with STDs as described in Example 9 hereinbelow, the protegrins show strong activity against the following microorganisms in addition to those tested hereinabove: pse~nm~n~R
aerugino~a, Kleb~iella pne~mn~iAe~ .~A7m~n~la tyrhim~rium, Staphylococcus aureus, Hi~toplasma capsulatum, Myobacterium av7um-intracellulare, and Mycobacterium tuberculosis. The protegrins showed only fair activity against Vibrio vulnificus and were inactive against Vibrio cholerae and Bo1-relia burgdorferi.
Example 3 Retention of ActivitY Under Certain Conditions The antimicrobial activity of the invention compounds was tested as set forth above, but under conditions of lOO~M
NaCl and in the presence of 90~ fetal calf serum. Figures 5a and 5b show that PG-1 and PG-3 retain their activity with respect to C. albicans and E. coli respectively, even in the presence of lOOmM NaCl. Neither NP-l nor HNP-1 have this property. Figure 5c shows that although NP-1 and NHP-2 lose their ability to inactivate C. albicans in 90~ fetal calf serum, inactivation by PG-3 is retained.

CA 0222247~ 1997-11-26 W O96/3751~8 PCT~US9~/07S94 i~ccordingly, the protegrins of the invention reta,in their antimicrobial properties under useful physiological concli~ions, including isotonic and borate solutions appropriate for use in eye care products.
rn addition, synthetic PG-l was tested with respect to its activity against E. coli ML-35 (serum sensitive) in under:Layered gels containing only 10 mM sodium phosphate buffer, pH 7.4 and a 1:100 dilution of trypticase soy broth, both :in the presence and absence of 2.5~ normal human seru,m, whic:h i5 below the lytic concentration for this strain of E.
col~. In the presence of seru,m, the minimal bacteriocidal concentration was reduced from approximately l.o ~g/ml to about 0.1 ~g/ml. This type of effect was not observed either for a linear fragment of cathepsin G or for the defen~3in HNP-1.
'~imilarly, using C. albicans as a target organism, under]Layers were prepared with 10 mM sodium phosphate with and without 10~ normal human serum. The m;n;m~l fungicidal concentration fell from about 1.3 ~g/ml in the absence of serum to 0.14 ~g/ml in its presence. The serum itself at this c:oncentration did not effect C. albicans.
Thus, not only is the action of the protegrins not inhibited by the presen,ce of serum, it is enhanced thereby.
Similar resuLts were obtained using L. monocytogeneB as the target: organism.
~ 'he protlegrins PG-1 and PG-3 were incubated for 4 hours at pH 2.0 with 0.5 ~g/ml pepsin and then neutralized. The resid~lal antil~icrobial activity against C. albicans, E. coli and L. monocytogenes was assessed and found to be fully ret~; ne~ . S.imilar experiments show that these compounds are not degraded ~y hllm~n leukocyte elastase or by hll~n leukocyte cat]hepsin G even when exposed to high concentration"3 of these enzymes and at a pH of 7.0 - 8.0 favorable for proteolytic activity. In addition, synthetic PG-3 amide an,d synthetic PG-3 acid were autoclaved and teste~, for anl_imicrobial activity against E. coli, L.
monoc~ogenese and C. albicans; retaining full antimicrobial CA 0222247~ 1997-11-26 W 096/37508 PCTrUS96/07594 activity in all cases. It is pos~ible that the stability of these compounds to protease degradation and to autoclaving is enhanced by the presence of disulfide bonds.

~x~le 4 AbilitY to Bind Endotoxin ~ he protegrins of the invention were tested for their ability to bind the lipid polysaccharide ~LPS) of the gram-negative bacterium E. coli strain 0.55B5. The assay was the Limul us amebocyte lysate (LAL) test for endotoxins conducted in the presence and absence of the test compounds. The test wa~ con~llcted using the procedure described in Sigma Technical Bulletin No. 210 as revised in December 1992 and published by Sigma Chemical Company, St. Louis, M0.
The LAL test is based on the ability of LPS to effect gelation in the commercial reagent E-Toxate which is prepared from the lysate of circulating amebocytes of the Horseshoe Crab Limul us poly~hem~ As described in the technical bulletin, when exposed to minute quantities of LPS, the lysate increases in opacity as well as viscosity and may gel depending on the concentration of endotoxin.
The technical bulletin goes on to speculate that the mechanism appears analogous to the clotting of m~m~l ian blood and involves the steps of activation of a trypsin-like preclotting enzymes by the LPS in the presence of calcium ion, followed by enzymic modifications of a "coagulogen" by proteolysis to produce a clottable protein. These steps are believed tied to the biologically active or "pyrogenic"
portion of the molecule. It has been shown previously that detoxified LPS (or endotoxin) gives a negative LAL test.
The test compounds were used at various concentrations from 0.25 ~g-10 ~g in a final volume of 0.2 ml and the test mixtures contained LPS at a final concentration of 0.05 endotoxin unit/ml and E-Toxate at the same concentration.
The test compounds were incubated together with the LPS for 15 minutes before the E-Toxate was added to a final volume ~ =

W ~961'i7508 PCTrUS96107594 after E-Toxate addition of 0.2 ml. The tube~ were then incubated for 30 minutes at 37~C and P~mtn~d for the form~at:ion of a gel.
Both isolated native protegrins (nPGs) and synthetically prepared protegrins (~PGs) were tested. The ~PGs were prepared with a carboxyl group at the C-terminus or wit:h an amidated C-terminus. The nPGs are amidated at the C-terminus. Also tested were six different rabbit defen~~ins (NPs) and four native human defensin~ (HNPs). The results are .~hown in Table 1.

Table1 F'eptide 10~9 5~9 2.5~ 1.0~ 0.5~90.25~9 nPG-1 no gel no sel no gel no gel + + +
nPG-.2 no Qel no ~elno ~el no ~el + + +
nPG-.3 no gel no ~el trsce + + + + + +
sPG-:3 2cidno ~elno 0el trace + + + + + +
sPG-:3 amide no gelno ~el no ~el + + + + +
NP-1 not not ++ ++ ++ ++
tested tested NP-2 trace + + + + + + + +
NP-31~ mo gel no gelno gel + + + + + +
NP-31b mo çlel no gel + + + + + + +
NP-4 not no- + + + + + + +
1tested tested NP-5 no gel trace + + + + + +
HNP-l no ~el + + + + ++ + +
HNP-.2 trace trace trace + + + +
HNP-.3 nogel + + ++ ++ ++
HNP-4 no gel trace trace + + + + +

As seen l.rom the results, all of the protegrins, both synthetic and native, and both in the amidated and no~m;ldated fc)rms are able to bind sufficiently to LPS to prevent any substantial gel formation at concentrations as low c18 2.5 ~1g/0.2 ml. nPG-1 and nPG-2 are effective at somewhat lower concentrations. The protegrins were substantially more effective than the NP or HNP test compc)u;nds; the most effective among these controls was -CA 0222247~ 1997-11-26 W O 9~/37508 PCTrUS~'~7S94 NP 3a, a peptide whose primary sequence most closely resembles that of the protegrins.
In a follow-up experiment, the concentration of LPS was varied from 0.05-0.25 endotoxin units (E.U.) and synthetic PG-3 amide was used as the test compound. The results are shown in Table 2.

Table2 ~nd~.lo.. i.. Units 0.25 E.U. 0.10 E.U. 0.05 E.U.
sPG-3 amide (2.5 ~)no ~el no ~el no ~el sPG-3 amide (1.0 ~)no ~el no ~el no ~el sPG-3 amide (0.5 ~) + + + + no ~el no added protein + + + + ++

These results show that since inhibition of gelation can be overcome by increasing the concentration of LPS, interaction with LPS is responsible for the lack of gelation, rather than interfering with the gelation enzyme ca~cade.

E~am~le 5 ActivitY of Linearalized Forms nPG-l and nPG-3 were converted to linear form using a reducing agent to convert the disulfide linkages to sulfhydryl groups, which were then stabilized by alkylating with iodoacetamide.
The ability of both cyclic and linearalized PG-l and PG-3 to inhibit gelation in the standard LAL a~say was assessed then as described in Example 4 and the results are shown in Table 3.

T~ble3 Peptide5~9 2.5~9 1.0~9 0.25~9 nPG-1 nogel no~el ++ ++ ++
c~-nPG-1 no gel no ~el + + + + + +
nPG-3 no ~el no ~el + + + + + +
c~77-nPG-3no ~el no ~el + + + + + +

_ CA 0222247~ l997-ll-26 W ~96S375~ PCTAUS96/07~94 1'hese results show that the linearalized and cyclic fornls of the protegrins are equally capable of inhibiting gelation and binding to endotoxin.
The antimicrobial activity of the linearalized forms was a]so compared with that of the native protegrins. Both linearalized and cyclic forms of the protegrins tested continue to show antimicrobial activity, although the effect:ivenes~ of these peptides as antimicrobials depends on the nature of the target organism and on the test condit:ions. The antimicrobial activity of native PG-1 and its linearalized form (cam-PG-l) and PG-3 and its linearalized form ( cam-PG-3 ) were tested according to the proceclure set forth in Example 1 as described by Lehrer, R.I. et al. J Immunol Meth (1991) 137:167-173. The results are set forth in Figures 6a-6f.
Figures 6a and 6b show the antimicrobial activity of these peptides in the concentration range 20 ~g/ml-125 ~g/ml with respect to E. coli ML-35P either in 10 mM phosphate-citrate buffer, pH 6.5 (Figure 6a) or in the presence of thi~ buffer plus 100 mM NaCl (Figure 6b). Both protegrins showed strong antimicrobial activity with respect to this organLsm; the linear form was slightly more potent in the preseIlce of buffer alone than was the cyclic form; on the other hand, the cyclic form was more potent than the linear form lmder isotonic conditions.
Figures 6c and 6d show the antimicrobial effect with resE)ect to L. monocytoyenes. In Figure 6c where the above-ment:ioned buffer alone was used, both cyclic and linearalized forms of the protegrins showed strong antim:icrobial activity and both were approximately equally effecl:ive over the concentration range tested (20 ~g/ml-125 ~g/~
- Figure 6d shows the effect with respect to L. ~no~ocytog~nes in the presence of this buffer plus 100 mM
NaC] over the same concentration range. The cyclic form retained strong antimicrobial activity with a slightly greater concentration dependence. Linearalization appeared CA 0222247~ 1997-11-26 W 096~7508 PCTrUS96/07S94 to lower the activity appreciably although high concentrations were still able to show an antimicrobial ef~ect.
The yeast C. albicans was tested with the results shown in Figures 6e and 6f. Figure 6e shows that all forms of these protegrins were antimicrobial in a dose-dependent manner over the above concentration range when tested in the presence of 10 mM phosphate buffer alone, although the linearalized peptides were very slightly less effective.
Figure 6f shows the results of the same assay run in the presence of buffer plus 100 mM NaCl. While the cyclized forms retained approximately the same level of antimicrobial effect, the activity of the linearalized forms was greatly ~;m;n;shed so that at concentrations below 100 ~g/ml of the protegrin, virtually no antimicrobial effect was seen.
However, at higher concentrations of 130 ~g/ml, a moderate antimicrobial effect was observed.
Thus, dep~n~; ng on the target microorganism and the conditions used, both the cyclized and linearalized forms of the protegrins have antimicrobial activity.

~Amnle 6 Antimicrobial ActivitY Under Conditions Suitable for Treatment of the EYe Contact lens solutions are typically formulated with borate buffered physiological saline and may or may not contain EDTA in addition. Protegrins in the form of the synthetic PG-3 amide and synthetic PG acid were tested generally in the assay described in Example 1 wherein all underlay gels contain 25 mM borate buffer, pH 7.4, 1~ (v/v) tryptocase 80y broth (0.3 ~ug/ml TSB powder) and 1~ agarose.
Additions included either 100 mM NaCl, 1 mM EDTA or a combination thereof. Other test compounds used as controls were the defensin NP-l and lysozyme. Dose response curves were determined.
Table 4 shows the estimated m; n; m~ 1 bacteriocidal concentrations in ~g/ml of the various test compounds.

CA 0222247~ 1997-11-26 W 096J.S7508 PCT~US96/07594 Table 4 ESTIM~1'ED MINIMAL FUNC~CInA~ CONCENTRATIONS (,uglml) Pl~ptide buffer + EDTA + NaCI + EDTA & NaCI
sPG-3 amide13.0 9.5 4.1 5.1 sPG-3 8cid15.0 9.5 4.6 ~.7 NP-11 35.0 45.0 >200 >200 1~5~ ",~ 75.0 45.0 >200 >200 Although protegrins are somewhat less active in 25 mM
borate buffered saline than in 25 mM phosphate buffer, the antimicrobial activity is ~nh~n~ed by adding physiological saline and modestly enhanced by 1 mM EDTA, as shown in the table~, A similar test was run with Candida albicans as the target: organi~m with the results shown in Table 5, which also c;hows estimates of m;n;m~l fungicidal concentrations.

Table 5 ESTIMA,TED MINIMAL FUN~;~C'lnA~ CONCENTRATIONS (llg/rnl) Pe!ptide 25 mM borateborate buffer borate buffer buffer + 120 mM NoCI+ EDTA & NaCI
nPG-3 32.0 9.0 8.0 sPG-3 ~Imide 19.0 7.7 7.0 sPG-3 ~Icid19.0 9.2 9.3 NP-1 23.0 60.0 65.0 HNP 1 25.0 >200 >200 Table 6 ~3hows results of similar experiments conducted with 1,. monocytogenes as the target.

Table 6 ESTIMATED MINIMAL BACTERICIDAL CONCENTRATIONS (~g/ml) Peptide25 mM borateborate bufferborate buffer buffer + 120 mM NaCI+ EDTA & NaCI
nPG-.3 25.0 7.0 5.7 sPG-:3 amide 21.0 5.7 5.2 sPG-:3 scid30.0 7.0 7.0 NP-1 20.0 11.0 3.8 HNP-1 11.0 >200 >200 CA 0222247~ 1997-11-26 W 096/37S08 PCTrUS96/07S94 The results shown indicate that these compounds are capable of exerting their antimicrobial effects under conditions typically associated with conditions suitable for eye care products.

~xam~le 7 Recoverv of cDNA Clones and of a New Proteqrin-Encodinq cDNA
cDNA Generation and PCR Am~lification.
Total RNA was extracted from the bone marrow cells of a young red Duroc pig with guanidinium thiocyanate. One ~g of total RNA was used to synthesize the first strand cDNA, with 20 pmol Oligo(dT) primer and 200 U Moloney-murine leukemia virus (M-MLV) reverse transcriptase (Clontech Laboratory, Palo Alto, CA) in a total reaction volume of 20 ~l. Two PCR
primers were prepared. The sense primer (5'-GT~.~ATTCATGGAGACCCAGAG (A or G) GCCAG-3l) corresponded to the 5' regions of PG-2 and PR-39 cDNA and contained an EcoRI restriction site. The antisense primer (5l-GTC~l~lAGA
(C or G) GTTTCACAAGAATTTATTT-3') was complementary to 3' ends of PG-2 and PR-39 cDNA immediately preceding their poly A tails and contained an XbaI restriction site. PCR
was carried out in a 50 ~1 volume using 1/10 volume of the above pig cDNA as template, 25 pmol primers and 2.5 units of AmpliTaq DNA polymerase (Perkin Elmer-Cetus). The reaction was run for 30 cycles, with 1 min denaturation (94~C) and ealing (60~C) steps and a 2 min extension step (72~C) per cycle.
cDNA Cloninq and Sequencinq. The amplified cDNA was fractionated by preparative agarose electrophoresis and stained with ethidium bromide. The main fragment was cut out, digested with EcoR I and Xba I endonucleases (New England Biolabs, Beverly, MA), subcloned into a M13mpl8 bacteriophage vector, and transformed into E. coli XL1-Blue MRF' competent cells (Stratagene, La Jolla, CA). DNA
sequencing w~s performed with a kit (U.S. Biochemical Corp., CA 0222247~ 1997-11-26 W 0961.S7S08 PCTrUS96~7594 Cle~eland, O~I). Nucleotide and protein sequences were ana:Lyzed with PC-GENE (Intelligenetics, Palo Alto, CA).
Northerrl blots. Ten ~g of total RNA was denatured in 50~ formamide, separated by electrophoresis through 1 agaxose gels in 0.62 M formaldehyde, and blotted onto GeneScreen Plus membranes (DuPont, Boston, MA) by capillary trallsfer. The membrane was baked at 80~C for 2 h, and hybridized with 32P-labeled probe in rapid hybridization buf~er (Amer~:ham, Arlington Height, IL).
'The results of sequencing the various clones encoding the various protegrins i5 summarized in Figure 7. The cDNA
se~lences o~ protegrins PG-1, PG-3 and PG-4 contain 691 bases as had previously been shown for PG-2 by Storici, P.
et al. Biochem Bio~hvs Res Comm (1993) 196:1363-1368. The cDN~s show an upstream sequence encoding 110 amino acids which appear~~ identical for all protegrins. Additional difierences, which are quite slight in nature, are shown in Fi~lr,e 7.
'rhe analysis showed the presence of the protegrin PG-4 haviLng an amino acid sequence of Formula (1) wherein Alo i8 a small amino acid and A~.1 is a hydrophobic amino acid as dist:inguishec,L from the previously known protegrins where theE~e residues are basic. The amino acid sequence of PG-4 is t:herefore RGGRLCYCRGWICFCVGRG, wherein 1, 2, or 3 amino acicls at the N-terminus may be deleted.
i~dditional clones were obtained by amplifying reverse transcribed porcine bone cell RNA using an upstream primer that: correspc,nds to the 5' end of PG-2 and another cathelin-assoc:iated peptide, PR39, (Agerbeth B et al., Eur J Biochem (19C11~ 202:849-854; Storici, P et al., Biochem Bio~hvs Res Com (L993) 186:1058-1065) and downstream primer that matches the region immediately preceding the poly A region. The resulling approximately 0.7 kb PCR product was subcloned into ~l3mpl8 and recombinant plaques were chosen for purif:ication and sequencing. In this m~nner~ the sec~ences for the precursors of PG-1, PG-3 and PG-4 were recovered.
All o~E these peptides are encoded by a nucleotide sequence CA 0222247~ 1997-11-26 W 096/37508 PCT~US96107594 which encodes a precursor cont~in;ng additional amino acid sequence upstream of Al of the compound of formula 1 (as shc)wn for PG-4 in Figure 7).

Exam~le 8 RecoverY of Genomic DNA Encodinq PG-l. PG-3 and PG-5 High molecular genomic DNA was purified from pig white blood cells with the QIAGEN blood DNA kit (QIAGEN, Chatsworth, CA). To amplify protegrin (PG) genes, PCR as performed using genomic DNA as a template.
The sense primer (5'-GTCGGAATTCATGGAGACCCAGAG(A or G)GCCAG-3') corresponded to the 5' regions of PG cDNAs, of Example 7 and provided an EcoRI restriction site. The antisense primer (5'-GTCGTCTAGA(C or G)GTTTCACAAGAATTTATTT-3') was complementary to 3' ends of PG
cDNAs immediately preceding their poly(A) tails and provided an XbaI restriction site. The rea~tion was carried out in a total volume of 50 ~1, which contained 200 ng of purified pig genomic DNA, 25 pmoles of each primer, 1 ~l of 10 mM
dNTP, 5 ~11 of 10X PCR buffer (200 mM Tris-~ICl, 100 mM(NH4)2, 20 mM MgS04, l~ Triton X-100, 0.1~ BSA), and 2.5 units of cloned Pfu DNA polymerase (Stratagene, La Jolla, CA).
Thirty cycles were performed, each with 1 min of denaturation at 94~C, 1 min of primer ~nne~ling at 55~C, 2 min of primer extension at 72~C, and a final extension step at 72~C for 10 min.
The amplified PCR product was digested with EcoRI and XbaI, excised from the agarose gel, purified, and ligated into pBluescript KS+ vector (Stratagene, La Jolla, CA) that had been digested with EcoRI and XbaI and purified. Both strands of DNA were sequenced by the dideoxy method using the Sequenase version 2.0 kit (United States Biochemical, Cleveland, OH), pBluescript universal primers and specific oligomer primers based on PG genomic and cDNA sequences.
Computer analysis of the DNA sequences was performed using the PC-Gene Program (Intelligenetics, Palo Alto, CA).

W 096~7!50~ PCTAUS96~07~94 A PCR product of about 1.85 kb was confirmed as prol_eyrin-re]ated by hybridization with a protegrin-specific oligonucleotide probe complementary to nucleotides 403-429 of lhe protegrin cDNA sec~ences. The PCR product was then subcloned into pBluescript vector, and recombinant plasmids were /subjected to DNA purification and sequencing. Gene sec~lences for three different protegrins were identified PG-1, PG-3 and PG-5. The nucleotide sec~ences and deduced ami~lo acid se~l~nc~q are shown in Figure 8.
Comparison of protegrin cDNAs and genes revealed that the coding regions of protegrin genes consisted of four exons, interrupted by three introns (Figures 8 and 9). The first exon contained the 5' noncoding region and codons for the f:irst 66 amino acids of the protegrin prepropeptide, incluciing a 29 residue signal peptide and the first 37 catheLin residues. Exons II and III were relatively small, only~ :L08 and 72 bp respectively, and together cont~tneA the next ~jO cathelin residues. The final two cathelin residues were on Exon IV, and were followed by the protegrin sec~ences. The exon-intron splice site sequences are shown in I'able 7, and conform to the consensus rule: all introns end on an AG Idoublet, preceded by a T/C rich stretch of 8-12 bases, while all introns start with GT, followed predominantly by A/G A/G G sec~ence.

T~ble7 Sttucture of the PG-1 Gene Exon Size 5' spIicc donor Intron Size 3' 5pOcc scce,~" ~r ?+ 198 AAGGCC~1~7~L.. g 1 405 ttg~ccagGACGAG
2 108 AACGGGs~L~agg.,l 2 152 c c,ll~,c~gCGGGTG
3 72 AATGAG~ 3 596 ~ ac&gGTTCAA

I'he high:Ly conserved cathelin region spans exons I-IV
and Exon IV contains the full secluence of the mature prot~egrin pept:ide followed by an amidation consensus sec~ence, a 3u untranslated region, and the putative polyadenylation site. The three introns range in size from CA 0222247~ 1997-11-26 WO9~/37508 PCTrUS96/07S94 - 48 -152 to 596 bp. If the protegrin genes are representative of other cathelin-like genes, the third intron of cathelin-associated peptides will be found to separate all but the last two residues of the highly conserved cathelin region from the variable antimicrobial peptides encoded in Exon IV.
Such a layout would favor recombination mechanisms involving association of diverse Exon IVs with the first three exons specifying cathelin cont~;n;ng prepro-regions.
The family of naturally occurring protegrins thus contains at least 5 members. Figure 10 shows a comparison of the amino acid sequences of the five protegrins found so far in porcine leukocytes. There is complete homology in positions 1-3, 5-9, 13 and 15-16.
Homology search of protegrin genes against the EMBL/G~nR~nk identified no significantly homologous genes.
More specifically, the gene structures and nucleotide sequences of protegrins were very different from those of defensins, which contain three exons in myeloid defensin genes, and two exons in enteric defensin genes. As expected, the search yielded the large family of cDNAs correspon~;ng to cathelin-associated bovine, porcine and rabbit leukocyte peptides.
To assess protegrin-related genes further, we screened a porcine genomic library of approximately 2.3 x 105 clones in EMBL-3 SP6/T7 with the 32P-labeled protegrin cDNA, and identified 45 hybridizing clones.
A porcine liver genomic library in EMBL3 SP6/T7 phages was purchased from Clontech (Palo Alto, CA). E. coli strain K803 was used as a host, and DNA from phage plaques was transferred onto nylon membranes (DuPont, Boston, MA). The fil~ers were hybridized with 32P-labeled porcine 691 PG-3 cDN~. The filters were washed several times, finally at 60~C
in O.lx SSC and 0.1~ SDS, and exposed to x-ray film with an intensifying screen at -70~C. Positive clones were subjected to two additional rounds of plaque purification at low density.

CA 0222247~ 1997-11-26 W 09613~75~8 PCTrUS96/07594 DMA purified from hybridizing clones was digested with various restriction ~n~o~l~cleases (New England Biolabs, Beverly, MA), fractionated on 0.8~ agarose gels, and transferred onto GeneScreen Plus membrane (DuPont, Boston, MA). The hybridization probes were labeled with 32p and inclucLed porcine PG-3 cDNA, and 5'-labeled protegrin-~ specific oligonucleotide complementary to nt 403-429 of PG-1, 2 and 3 cDNAs. For the cDNA probe, the hybridization and washing conditions were carried out as for the library screening. For the oligonucleotide probe, the membranes were washed at 42~C in O.lx SSC, 0.1~ SDS.
~ outhern blot analysis was carried out with purified DNA from positive clones by hybridization with protegrin cDNA and a pr~tegrin specific oligonucleotide complementary to nt 403-429 of protegrin cDNA sequences. Although all of the clones hy~bridized with the complete cDNA probe, only about half of them hybridized with the protegrin-specific probe. A specific oligonucleotide probe for porcine prophenin, another cathelin-associated porcine leukocyte-derive~d antimicrobial peptide, hybridized to several of thenonpr~tegrin clones. These results confirm a) that the conserved proregion homologous to cathelin is present within the same gene as the mature antimicrobial peptides and is not a~ded on by posttranscriptional events, and b) that the protegrin~ ac~_ount for about half of the cathelin-related genes in the pig.
~ synthetic peptide corresponding to the amino acid sequence of ~?~-5 was prepared and tested with respect to antimicrobial activity against E. col i, L. monocytogenes and 3 0 C. alk~ican~ . The results were compared to those obtained with a syntheicically prepared PG-1. The results are shown in Figures lla-llc. As shown in these graphical representations of the results, PG- 5 has comparable antimicrobial activity to PG-1 against all three organisms 35 tested.

Example g CA 0222247~ 1997-11-26 W 096/37508 PCTrUS96/07594 Pre~aration of EnantioPG-1 Using standard solid phase techni~ues, a protegrin having the amino acid sequence of PG-1, but wherein every amino acid is in the D form was prepared. This form of protegrin was tested against E. coli, L. monocytogenes, C.
albicans and other microbes in the absence and presence of protease and otherwise as described for the radiodiffusion assay in agarose gels set forth in Example 1. The results are shown in Figures 12a-12g.
Figure 12a shows that both native PG-1 and enantioPG-1 in the absence of protease are equally effective in inhibiting the growth of E. coli. Figure 12b shows that neither trypsin nor chymotrypsin inhibits the antibacterial effect of enantioPG-1. Figure 12c shows that in the presence of these proteolytic enzymes, the ability of native PG-1 to inhibit the growth of L. monocytogenes is adversely affected, although, as shown in Figure 12d, in the absence of these proteases PG-l is comparably active to an en~ntioPG-1.
~rle lo Activity of the Proteqrins Against STD Pathoaens Table 8 summarizes the activity of the protegrin PG-1 as compared to the de~ensin HNP-1 against growth of STD
pathogens. In these results, "active" means that the peptide was effective at less than 10 ~g/ml; moderately active indicates that it was active at 10-25 ~g/ml; and slightly active means activity at 25-50 ~g/ml. If no effect was obt~; n~ at 50-200 ~g/ml the compound was considered inactive.

CA 02222475 l997-ll-26 W O 961l37~508 PCTAUS~6~7S94 T8ble 8 .Activity a~ain!;t human STD~r.,l~.in PG~ . HNP-1 p~ c~g- -. .s Hl~- 1 Active Slight~y active ChlD~ydia tr~3chom~tis Active Slightly active T,e,Don~",~ pa/lid~/m Active Inactive N19 '.S~ ~."ia gonorrhoeae Active Inactive Tricho",onas ~J- ~'sM~d~ al~lyInactive active Herpe~s simplex type 2 Mo ~'~ al~ly Slightly active active Henpe~i simplex 1:ype 1 Inactive Slightly active //~n,o/~t :~s ducreyi Not tested Not tested Hunnan ~r ~; .. a virus Not tested Not tested ~h 7 amYdia trachoma ti 8 Unlike other bacteria a~sociated with STDs, Chlamydia re~lires an intracellular habitat for metabolic activity and binary fi~sion. The life cycle is as follows: there is an extralcellular form which is a metabolically inactive part:icle so~ewhat sporelike in its beha~ior, referred to as an elementary body (EB). The EB attaches to the host cell and is ingested to form an internal vacuolar space often cal].ed an "in,clusion". The bacterium reorganizes to the delic.~te reticulate body (RB) which i~ no~;nfective but metabolically active and which over a 48-72 hour period undergoes reformation to the EB state. The EBs are then released from the cell. Rather than a peptidoglycan layer, ChlG~rdia contains multiple disulfide linkages in cysteine-rich proteins for protection in the EB stage.
The protegrins of the invention were tested for their antimi.crobial activity against Chlamydia using the "gold st~nA;~d" chlamydial culture system for clinical specimens described by Clarke, L.M. in Clinical Microbiolo~v Procedures Handbook II (1992), Isenberg, H.T. Ed. Am. Soc.
Microbiol. Wa~hington, D.C.; pp. 8Ø1 to 8.24.3.9.
Briefly, McCoy cells (a mouse cell line) in cycloh~; m; de CA 0222247~ 1997-11-26 W 09~6/37508 PCTrUS96/07S94 EMEM with 10~ fetal bovine serum (FBS) are used as hosts.
Prior to chlamydial inoculation, the maintenance medium is aspirated without disruption of the cell layer and the cell layer is maintained on a cover slip in a standard vial.
Each ~rial is then inoculated with 100-300 IlL inoculum and centrifuged at 3500 x g for one hour at 20~C. The fluid is then aspirated and 1 ml of EMEM is added. The vials are capped and incubated at 37~C for 48 hours. After 48 hours the medium is again aspirated, coverslips are rinsed twice wil:h PBS and fixed with 300 ~lL EtOH for 10 minutes. The EtOH is aspirated and the vials are allowed to dry; then one drop PBS plus 30 ~IL Syva Microtrak monoclonal antibody to the major outer membrane protein of Chlamydia is added for 8t~;n;n~. After 37~C incubation for 30 minutes, the cells are washed with distilled water and ~m; ned for inclusions which are easily recognizable as bright, apple-green-st~; n; ng cytoplasmic vacuoles. They represent the equivalent of a colony of free-li~ing bacteria on st~n~A~d bacterial culture media.
In the assays conducted below, C. trachomatis serovar L2 (L2/434BU) described by Kuo, C.C. et al . in NoncJynococcal Urethritis and Related Infections (1977), Taylor-Robinson, D. et al . Ed. Am. Soc. Microbiol. Washington, D.C., pp. 322-32~i was used. The seed is prepared from a sonicated culture in L929 mouse fibroblast cells, and partially purified by centrifugation. Since host protein is still present in the seed aliquots, each seed batch is titered at the time of preparation with serial ten-fold dilutions to 2 x 10-9. The seed containing 9.2 x 106 IFU/ml is thawed quickly at 3 7~C
and diluted to 10-2 with sucrose/phosphate salts/glycine to produce IFU of about 200 after room temperature preincubation and to dilute background eukaryotic protein.
In the initial assays, the peptides to be tested were prepared as stock solutions in 0.01~ glacial acetic acid.
100 ~L of the diluted chlamydial seed was aliquoted into 1.5 ml eppendorf tubes and 200 ~lL of the antibiotic peptide was CA 0222247~ 1997-11-26 W O 96137'jO8 P ~ AUS96~07~94 added per tLlbe. Aliquots of the peptide stock (and controls) were incubated with the seed at room temperature for one hour~ two hours and four hours. About 10 minutes before the end of each incubation period, maintenance media werle aspirated from the McCoy vials in preparation for standard inoc:ulation and culture. Culture was then performed in the presence and absence of the peptides; in some cases, t:he peptides were added to final concentration in the culture media in addition to the preculture incubation. The test was evaluated microscopically.
The re~3ults using 50 ~g of protegrin per addition were dramatic. In control cultures, where no peptides were added, 222-460 inclusions were counted. In all protocol where protegrin was added either before the Chlamydia seed was ai~ded to the cells or both before and after, no inc:Lusions were found. Similar results were obt~; n~ with 20 ~Ig additions of tachyplesin. The defensins NP-1 arld HNP--1 had le~lser protective effects. In summary, the prot:egrins tested show antimicrobial against Chlamydia.
rn the ~ext serie~3 of experiment~, various conce1ltrations of protegrin (1 ~g, 12.5 ~g, 25 ~g and 50 ~g) were LLsed in the two-hour preincubation. Concentrations as low a~3 12.5 ~g lowered the number of inclusions to zero.
Even .iLt a concentration of 1 ~g/ml, the number of inclusions was lowered dramatically from about 110 to about 30.
:~n the next set of experiments, the effect of the pre~iellce of serum was tested. The Chlamydia seed was prei.ncubated for two hours with and without 10~ FBS and also witkL or without protegrin at 25 ~Lg. Protegrin was highly effect:ive both with and without serum, whereas human defen~3in HNP-2, used as a control, was reasonably effective in the absence of serum but only marginally effective in its pres~erlce .
~'he experiments were repeated but adding 25 ~g of proteqrin one after the start of the chlamydial culture, i.e., after centrifugation and final medium mix and one hour into t:he beginning of the 48-hour culture period. Protegrin CA 0222247~ l997-ll-26 W O9G/37508 PCTrUS96/07S94 reduced the number of inclusions by approximately 57~ from untreated controls although HNP-2 was completely ineffective. Finally, the protegrin (at 25 ~lg) was added to the chlamydial seed and the mix then immediately cultured.
In this case, without preincubation and without the one-hour post-infection gap, protegrin was min;m;llly effective without or without serum.
The effect of serum is particularly important since for a topical agent to be effective in combatting Chlamydia infection, it must act in the presence of serum.
In addition, there are several mouse-based models for Chlam~dia infection which can be used to assess the efficacy of the protegrins. These include those described by Patton, D.L. et al. in Chlamydial Infections (1990) Bowie, W.R. et al. Eds. Cambridge University Press NY pp. 223-231; Swenson, C.E. et al. J. Infect. Dis. (1983) pp. 1101-1107, and Barron, A.L. et al. J. Infect. Dis. (1981) 143:63-66.

Neisseria qnnorrhoeae In more detail, the ability of the protegrins to inhibit N. gonorrhoeae was tested by a modification of the method of Miyasaki et al., Antimicrob A~ent Chemother (1993) ~7:2710-2715. Nonpiliated transparent variants of strains FA 19 and F 62 were propagated on GCB agar plates containing glucose and iron supplements overnight at 37~C under 3. 8~
V/V C02. These strains were chosen for their adaptability to the assay.
The overnight growth i8 removed from the agar plate and suspended in GCB broth cont~; n; ng supplements and sodium bicarbonate and grown with shaking at 37~C to mid log phase.
The culture is diluted 1:100 in GCB broth to give about 106 CFU/ml and serial dilutions were plated onto GCB agar.
The peptides are dissolved in 0.01~ v/v acetic acid to give a 1 mg/ml stock solution and serially diluted. Ten ~1 of each dilution is added to a sterile polystyrene tube containing 90 ~1 of diluted bacteria and the tubes are shaken at 37~C for 45 minutes. The contents are serially W O96 MS'0~ PCT~US96/07S~4 diluted 1:10 and plated on to GCB agar plates which are incubated in a C02 incubator. CFU are counted after 24 hou:rs and the log bactericidal activity calculated.
Native E~G-l, synthetic PG-l, synthetic PG-3 amide and ~ynthetic PG-3 without amidation all gave over a 5 log reduction in CFU per ml in this assay. Native PG-2 (containing 16 amino acids) gave a 2.6 fold reduction.
In addition enantioPG-1, the unidisulfide PG-1 (C6-Cl5), and unisulficte PG-l (C8-C13) gave over a 5-fold log reduction in ~FU/ml in this assay.

Tre~onema l~al lidum ]3acteriocidal activity against this organi~m, which is the el_iologic agent of syphilis, was also tested. Peptides were evaluated at a series of concentrations of 1.758 ~g to 56.25 ~g in 90 ~l of unheated normal rabbit serum. The serum ser~ed as a nutrient for the spirochetes to allow thei.r survival during incubation as well as providing a source of complement. Ten ~l of a suspension o~ T. pallidum cont~iln;ng about 5 x 107/~l organisms was added to each tube and the mixtures with the appropriate peptides were incubclted at 34 C under 95~ N2 and 5~ C02. At time zero, just prior to incubation, 4 hours and 16 hours, 25 r~n~omly select:ed organisms were ~Am;ned for the presence or absence of mot:ility. The 50~ immobilizing end point (IE50) was calcu]ated to indicate the concentration needed to immobilize 50~ of the spirochetes. In the presence of PG-1, the IE:50 at 0 and 4 hours was 2.717 ~g and c 1.758 ~g, respectively. Tachyplesin IE50's were 5.231 ~g and 2.539 ~g for 0 and 4 hours. This was in contrast to HNP and NP
preparations ~which showed little immobilizing ability.

Herpe~ Sim~lex Virus ~sing vi:ral stocks prepared in VER0 cells, grown in m;n; m~l eggenlial medium (MEM) with 2~ fetal calf serum, the effect of var:ious peptides on HSV 1 MacIntyre strain, a pool of ten clinical HSV 1 isolates, HSV-2G, and a pool of ten CA 0222247~ 1997-11-26 W 096/37S08 PCT~US9~7~94 clinical HSV 2 isolates, all sensitive to 3 ~M acyclovir were tested. Two fibroblast cell lines, human W138 and e~uine CCI~57, were used as targets and tests were done by di~ect viral neutralization and delayed peptide addition.
In the direct neutralization format, the virus was preincubated with the peptides for 90 min before it was added to the tissue culture monolayers. In the delayed peptide addition format, the virus was added and allowed 50 min to adsorb to the target cells, then the monolayers were washed and peptides were added for 90 min. Finally, the monolayer was washed to ~e~l-ove the peptide and the cells were fed with peptide-free MEM and cultured until the untreated infected monolayers exhibited 4+ cytopathic effect (CPE) ( about 60 hours).
Antiviral activity was seen in both formats, but was more pronounced with the delayed peptide addition mode. In experiments performed with W138 and CCI,57 cells in the direct neutralization format, PG-l completely prevented HSV-2G from causing CPE at concentrations of 50 ~lg/ml and 25 llg/ml, but these concentrations afforded no protection against HSV-l, which produced 4+ CPE.
In the delayed peptide addition format, PG-l completely prevented CPE by HSV-2G at 3 5 llg/ml and 50 llg/ml and it also fully protected against the clinical HSV-2 pool at both concentrations.
Thus, PG-l protected human and ~n;m~l cells from infection by laboratory and clinical strains of HSV-2, even when the peptides were added as late as 60 min after the virus had been introduced into the cell culture.
Tri chom~n~ ~ vaqinalli~
Trirhomon~ vaginallis strain Cl (ATCC 30001) was grown as described by Gorrell, T.E. et al, Carlsberq Res Comm (1984) 49:259-268. In experiments performed in RPMI + 1~
heat-activated fetal calf serum, within a few minutes after exposure to 50 ~g/ml PG-l, T. vaginallis (heretofore viyorously motile) became stationary. Soon thereafter, the CA 0222247~ l997-ll-26 W 0961"7508 PCTrUSg~'~7~4 org~misms bec:ame permeable to trypan blue, and, over the en~ling 15-30 minutes, lysed. As expected, such organisms failed to grow when introduced into their customary growth medlum (DiArnon~s medium). Organisms exposed to 25 llg/ml of PG-~3 :retainecl their motility.
Initial studies with two highly metronidazole-resistant clinical isol.ates of T. vagi~allis, strains MR and TV showed both were susceptible to PG-1, including the C8-C13 and C6-Cl5 uni-disulfides and enantioPG-1 at concentrations o~ 100 and 50 ,ug/ml.

Example 11 ~ntiretroviral Activitv Both syn.thetic and native PG-1 and native PG-2 were teE;t:e~ for an.tiviral activity against strains of HIV using the method described in Miles, S.A. et al., Blood (1991) 78:32t)0-3208. Briefly, the mQ~o~llclear cell fraction is recovered from normal donor leukopacs from the American Red Croa~s using a Ficoll-hypaque density gradient. The mo~o~ clear cells are resuspended at 1 x 106 cells per ml in RPMI ~.640 medium with 20~ fetal bovine serum, 1~ penn/strep with. f.ungizone and 0.5~ PHA and incubated 24 hours at 37~C
in 5~ CO2. T]he cells are centrifuged, washed and then expa.ncled for 24 hours in growth medium.
Non-laboratory adapted, cloned HIV~R-CSF and HIVJR_FL
were electroporated into the human peripheral blood mo~onl~clear clells prepared a~ described above. Titers were determ;ne~ arld in general, multiplicities of infection (MOI) of about 4,000 infectious units per cell are used (which 30 corresponds to 25-40 picograms per ml HIV p24 antigen in the supernatant).
In the assay, the HIV stocks prepared as above were - dilute!d to the correct MOI and the PBM are added to 24 well plates at a concentration of 2 x 106 per ml. One ~1 total 35 volume i5 added to each well. The peptide to be tested is added in growl_h medium to achieve the final desired concen.tration. Then the appropriate number of MOI are CA 0222247~ 1997-11-26 W 096/37508 PCTrUS9C~'~7S94 added. To assay viral growth, 200 ~1 of supernatant is removed on days 3 and 7 and the concentration of p24 antigen i8 determined using a commercial assay (Coulter Immunology, Hialeah, Florida). Controls include duplicate wells containing cells alone, cells plus peptide at 5 ~g/ml cells with virus but not peptide and cells with virus in the presence of AZT at 10 5 M - 10 M.
Using this assay, it was ~emn~trated that both natural and synthetic PG-1 completely inhibit HIV infection at concentrations between 1-5 ~g/ml; ICgo was c 5 ~g/ml. The time of addition of peptide was then varied. Cells pretreated for 2 hours prior to addition of virus, at the time of addition of virus, or 2 hours after infection showed antiviral activity for the peptide. However, if PG-1 was added 24 hours after infection, there was no antiviral activity.
Further, PG-2 shows similar activity but at a level approximately 5-fold less. Alternative antibiotics such as human defensins and rabbit defensins lacked potent activity in this assay. The results were similar for both HIVJR_CSF
and HIVJR_FL which are non-laboratory adapted isolates (Koyanagi, Y.S. et al, Science (1987) 236:819-822).
The protegrins show similar activity with respect to other retroviruses.
~mnle 12 P~e~aration of Modified Proteqrins: Kite and Bullet Forms The kite and bullet forms of PG-1 wherein all X are alanine were synthesized using conventional Fmoc ch~ tr The crude synthetic peptide was reduced by adding dithiothreitol (DTT) e~ual in weight to the synthetic peptide which had been dissolved at 10 mg peptide/ml in a solution containing 6 molar guanidine HCl, 0.5 molar tris buffer, and 2 mM EDTA, pH 8.05 and incubated for two hours at 52~C under nitrogen. The mixture was passed through a 0.45 ~ filter, acidified with 1/20 (v/v) glacial acidic acid and subjected to conventional RP-HPLC purification with a _ CA 0222247~ 1997-11-26 W O 96137508 PCTAUS96~7594 C-18 column. HP~C-purified, reduced synthetic bullet and kite PG-l were partially concentrated by vacuum centrifugation in a speed vac and allowed to fold for 24 hours at room temperature in ambient air in 0.1 M Tri~
pH 7.7 at low concentration (0.1 mg peptide/ml) to m;n;m;~e fonnation of interchain cystine disulfides. The mixture was then concentrated and acidified with HOAC to a final concentratioIl of 5~ and subjected to RP-HPLC purification.
The puri~ty of the final products bullet and kite PG-1 was verified by AU-PAGE, analytical HPLC, and FAB-mas~ spec.
AU-]?A~E showed a single band for the final product in each case. The observed MH~ mass values were 2093 in both cases.

~m~le 13 ~ntimicrobial Activity of the Kite and Bullet Forms The kite and bullet PG-1 compounds prepared in Example 12 we:re tested for antimicrobial activity using the radial diffusion assay described in Example 1 as published by Lehre:r, R.I. et al ., ~ Tmmun~l Meth (1991) 137:167-173, excepl_ that the underlay agars contA; ne~ 10 mm sodium phoE;p~late buffer with a final pH of 7.4. As described in Exa~p:Le 1, 0.3 mg/ml tripticase soy broth powder and 1~
agaro~3e were used as well in the underlay agar. In some cases 100 mM NaCl or RPMI plus 2.5~ normal human serum (NHS) was aclded to the agar.
~n a first set of determinations, the bullet and kite forms of PG-1 were tested for antimicrobial activity against L. mo~locytogenes, E. f~ecium (VR) or S. aureus under these three sets of conditions. Figure 13 shows the result.
~s shown, the bullet and kite forms were roughly equally effective against these three bacteria using standard assay conditions. When 100 mM NaCl was added to the ac~ar, however, the kite forms appeared slightly less active than t.he bullet forms which appear to have slightly ~nh~nc!ed antimicrobial activity against all three stains except S. aur,ous under these conditions. Similarly, when RPMI plus 2.5% NHS were added, the bullet forms were again more effective than the kite forms. The activity of the kit CA 0222247~ 1997-11-26 W 096137508 PCTrUS96/07S94 form versus E. faecium was significantly less under these conditions.
As shown in Figure 14, these forms of PG-1 were also tested against E. coli, K. pneumoniae and P. aeruginosa.
All three microorganisms were inhibited by both kite and bullet forms under standard conditions. This antimicrobial activity was maintained also at 100 mM NaCl and RPMI plus NHS.

Example 14 Synthesis of the Snake Form of PG-l The snake form of PG-l wherein all X are alanine was performed using standard methods by Synpep Inc., Dublin, CA
and the MH+ value in FAB-mass spec was 2031.3 as expected.
The snake form was purified to homogeneity by RP-HPLC.

Example 15 Antimicrobial ActivitY of Snake PG-l Snake PG-l was tested with respect to the same six organisms and using the same conditions as set forth in Example 13 with respect to the bullet and kite forms of PG-l. The results are shown in Figures 15 and 16. In this case, the native two-cystine form of PG-l (native) was used as a control. While the snake form shows somewhat superior activity with respect to L. monocytogenes, E. faecium, and 5. aureus under standard conditions, it is notably less effective than the native form in the presence of either 100 mM NaCl or RPMI plus NHS. The same pattern is followed, as shown in Figure 16 when the test organisms are E. coli, K. pneumoniae, and P. aeruginosa.

E~am~le 16 Minimal InhibitorY Concentrations of Proteqrins The minimal inhibitory concentrations (MICs) of a variety of protegrins were determined against the following organisms: methicillin resistant Staphylococcus aureus -CA 0222247;i l997-ll-26 W 096~.,7508 PCTAUS96/07594 (MRS'A), Pser~r~QInor~ aeruginosa (P~a), vancomycin resistant Enterococcus fecium (VREF), Candida albicans (Candid) and E~ch!erichia coli (E. Co), and are shown in Table 9.

Table9 P~lid~with17-18AminoAcids SEQ UEN CE M RSA Psa VREF Candid E. Co IB-24,' RGGRLCYC"RRR~ v~:v~-OH 1.5 0.11 1.2 0.6 IB-249 RGGGL~Y~K~k~v~v~K-oH 3.29 0.4 IB-22~ RGGGL~Y~:~u~v~K 1.93 0.14 1.6Z
IB-224 RGGGLCYCRRPr~v~:v~ 3.1 0.06 7.69 0.15 IB-324 RGGGLCYCRPR~v~v~K-OH 17.7 3.51 IB-341 RGGRLCY.CRXR~:v-~v~i~-OH(X~NMeG) 5.33 2 IB-342 RGGRLCY.CRXR~:vLv~ (X=NMeG) 4 1.67 0.83 IB-384 RGGRLCYCXGR~:v~:v~ (X=Cit) IB-398 RG~Kv~Y~ ~v-~v~ 8 IB-3991 RG~v~Y~:K~K~v~v~-OH
IB-218 RGGK3L~Y~:~Y~v~v~ 3.48 l.Z 15.96 IB-349 RGGRLCY.CRXR-Cha-CVCWGR (X-NMeG) IB-350 R ~ ~.~,v~:Kx.K-Cha-CYCVGR (X~NMeG) IB-394- RGR~k~._v~:KGR-cha-CYCVGR
IB-416 RGGRL~y~ uk~c-~nMev-cvGR
IB-40CI RG~Kv~Y~:~GRFCVCV 8 2 IB-401 RG~ ;KV~ 'y~:K~KFcvcv-oH 64 ~nl-Dt ~-~1 f~ A- ProtO~rin~
IB-214 RGGGLCYPRGWIAFCVGR 2.1 0.59 32.6 0.81 IB-216 RGGGLCYP.~RGFIAVCFGR 19 14 65.8 3.27 IB-225 RGGGLCYP.~RPRFAVCVGR
IB-226; RGGGLCY~'RPR~ v~ 8.7 0.07 1.53 IB-227 RGGGLCYP.~RKGFAVCVGR > 128 0.01 2.65 IB-288 RGGRLCYARRRFAVCVGR-OH 0.05 1.6 0.4 IB-289 RGGRLCY'~RRRFAVCVGR 0.05 1.6 0.4

Claims (16)

Claims

1. A purified and isolated or recombinantly produced compound of the formula A1-A2-A3-A4-A5-C6-A7-C8-A9-A10-A11-A12-C13-A14-C15-A16-(A17-A18) (1) and the N-terminal acylated and/or C-terminal amidated or esterified forms thereof, which is either in the optionally -SH stabilized linear or in a cystine-bridged form wherein A1 is a basic amino acid;
each of A2 and A3 is independently a small amino acid;
each of A5, A7, A14 is independently a hydrophobic amino acid;
A4 is a basic or a small amino acid;
each of A9, A12 and A16 is independently a basic, a hydrophobic, a neutral/polar or a small amino acid;
each of A10 and A11 is independently a basic, a neutral/polar, a hydrophobic or a small amino acid or is proline;
A17 is not present or, if present, is a basic, a neutral/polar, a hydrophobic or a small amino acid;
A18 is not present or, if present, is a basic, a hydrophobic, a neutral/polar or a small amino acid, or a modified form of Formula (1) and the N-terminal acylated and/or C-terminal amidated or esterified forms thereof wherein at least one of the 4 cysteines is independently replaced by a hydrophobic amino acid or a small amino acid;
with the proviso that the compound of Formula (1) must have a charge of +3 or greater.

2. The compound of claim 1 which contains two cystine bridges.

3. The compound of claim 1 which contains one cystine bridge, which is C6-C15 or C8-C13.

4. The compound of claim 1 which is in the linear form.

5. The compound of any of claims 1-4 wherein the C-terminal carboxyl is of the formula selected from the group consisting of COOH or the salts thereof; COOR, CONH2, CONHR, and CONR2 wherein each R is independently hydrocarbyl(1-6C);
and/or wherein the amino group at the N-terminus is of the formula NH2 or NHCOR wherein R is hydrocarbyl(1-6C);
and/or wherein each of A1 and A9 is independently selected from the group consisting of R, K and Har;
and/or wherein each of A2 and A3 is selected independently from the group consisting of G, A, S and T;
and/or wherein A4 is R or G;
and/or wherein each of A5, A14 and A16 is independently selected from the group consisting of I, V, NLe, L and F;
and/ox wherein each of A7 and A12 is independently selected from the group consisting of I, V, L, W, Y and F;
and/or wherein A10 is R, G or P;
and/or wherein A11 is R or W.

6. The compound of claim 1 which is selected from the group consisting of PG-1: RGGRLCYCRRRFCVCVGR
PG-2: RGGRLCYCRRRFCICV
PG-3: RGGGLCYCRRRFCVCVGR
PG-4: RGGRLCYCRGWICFCVGR
PG-5: RGGRLCYCRPRFCVCVGR
PC-39: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-R
PC-41: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-G
PC-100: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-Y

PC-101: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-T
PC-102: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-A
PC-103: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-L
PC-104: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-I
PC-105: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-F
PC-106: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-W
PC-108: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-R
R-G-G-R-L-C-W-C-R-R-R-F-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-W-C-V-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-W-C-V-G-R
R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-W-G-R
IB-247: R-G-G-R-L-C-Y-C-R-R-R-F-C-V-C-V-G-R-OH
IB-249: R-G-G-G-L-C-Y-C-R-R-R-F-C-V-C-V-G-R-OH
IB-223: R-G-G-G-L-C-Y-C-R-R-G-F-C-V-C-F-G-R
IB-224: R-G-G-G-L-C-Y-C-R-R-P-F-C-V-C-V-G-R
IB-324: R-G-G-G-L-C-Y-C-R-P-R-F-C-V-C-V-G-R-OH
IB-341: R-G-G-R-L-C-Y-C-R-X-R-F-C-V-C-V-G-R-OH (X=NMeG) IB-342: R-G-G-R-L-C-Y-C-R-X-R-F-C-V-C-V-G-R (X=NMeG) IB-384: R-G-G-R-L-C-Y-C-X-G-R-F-C-V-C-V-G-R (X=Cit) IB-398: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V-G-R
IR-399: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V-G-R-OH
IB-218: R-G-G-G-L-C-Y-C-F-P-K-F-C-V-C-V-G-R
IB-349: R-G-G-R-L-C-Y-C-R-X-R-Cha-C-V-C-W-G-R (X=NMeG) IB-350: R-G-G-R-W-C-V-C-R-X-R-Cha-C-Y-C-V-G-R (X=NMeG) IB-394: R-G-G-R-W-C-V-C-R-G-R-Cha-C-Y-C-V-G-R
IB-416: R-G-G-R-L-C-Y-C-R-R-R-F-C-NMeV-C-V-G-R
IB-400: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V
IB-401: R-G-G-R-V-C-Y-C-R-G-R-F-C-V-C-V-OH
PC-49: R-G-G-R-L-C-W-A-R-R-R-F-A-V-C-V-G-R
PC-50: R-G-G-R-L-C-Y-A-R-R-R-W-A-V-C-V-G-R
PC-52: R-G-G-R-L-A-W-C-R-R-R-F-C-V-A-V-G-R
PC-53: R-G-G-R-L-A-Y-C-R-R-R-F-C-V-A-W-G-R
PC-55: R-G-G-R-L-A-W-A-R-R-R-F-A-V-A-V-G-R
PC-56: R-G-G-R-L-A-Y-A-R-R-R-W-A-V-A-V-G-R
PC-57: R-G-G-R-L-A-Y-A-R-R-R-F-A-V-A-W-G-R
IB-214: R-G-G-G-L-C-Y-A-R-G-W-I-A-F-C-V-G-R
IB-216: R-G-G-G-L-C-Y-A-R-G-F-I-A-V-C-F-G-R

IB-225: R-G-G-G-L-C-Y-A-R-P-R-F-A-V-C-V-G-R
IB-226: R-G-G-G-L-C-Y-T-R-P-R-F-T-V-C-V-G-R
IB-227: R-G-G-G-L-C-Y-A-R-K-G-F-A-V-C-V-G-R
IB-288: R-G-G-R-L-C-Y-A-R-R-R-F-A-V-C-V-G-R-OH
IB-289: R-G-G-R-L-C-Y-A-R-R-R-F-A-V-C-V-G-R

and the amidated forms thereof either in linear or cystine-bridged form.

7. The compound of any of claims 1-6 wherein all amino acids are in the D-configuration.

8. A recombinant expression system for production of an antimicrobial peptide having the amino acid sequence of the compound of any of claims 1-6 which expression system comprises a nucleotide sequence encoding said peptide operably linked to control sequences for effecting expression.

9. A recombinant host cell modified to contain the expression system of claim 8.

10. A method to produce an antimicrobial or antiviral peptide or intermediate peptide therefor which method comprises culturing the modified host cells of claim 9 under conditions wherein said peptide is produced; and recovering the peptide from the culture.

11. The method of claim 10 which further comprises effecting cystine linkages of said peptide and/or modifying the N-terminus and/or C-terminus of said peptide.

12. A pharmaceutical composition for antimicrobial or antiviral use which comprises the compound of any of claims 1-7 in admixture with at least one pharmaceutically acceptable excipient.

13. A composition for application to plants or plant environments for conferring resistance to microbial or viral infection in plants which comprises the compound of any of claims 1-7 in admixture with at least one environmentally acceptable diluent.

14. A method to prevent the growth of a virus or microbe which method comprises contacting a composition which supports the growth of said virus or microbe with an amount of the compound of any of claim 1-7 effective to prevent said growth.

15. A method to inactivate the endotoxin of gram-negative bacteria, which method comprises contacting said endotoxin with an amount of the compound of any of claims 1-7 effective to inactivate said endotoxin.

16. Antibodies specifically reactive with the compound of any of claims 1-7.