IgA-protease

IgA proteases belong to the defensive pathogenicity factors with which pathogens impede or prevent an effective immune response of the host. IgA proteases cleave and inactivate mucosal antibodies. IgA-1 proteases cleave the antibody at the hinge region (in IgG the flexible region in the middle of the H-chain) so that the Fab and Fc fragments are separated (S. pneumoniae, H. influenza, N. meningitidis, N. gonorrhoeae and others).

Inactivation by IgA binding proteins results from their binding to the Fc region of IgA1 and IgA-2 antibodies(S. pneumoniae, S. pyogenes, H. pylori). In addition, there are bacterial IgA glycosidases that deglycosylate carbohydrate groupings of IgA antibodies.