IgG antibodies are involved in the secondary immune response (IgM is the main antibody involved in primary response). IgG can bind pathogens, like for example viruses, bacteria, and fungi, and thereby protects the body against infection and toxins.

Wheat germ agglutinin (WGA) is a fluorescently-labelled lectin that selectively binds to N-acetylglucosamine acid in the peptidoglycan layer of gram-positive bacteria as well as PNAG in both gram-positive and gram-negative bacteria [88–90].