Interaction of human, rat, and mouse immunoglobulin A (IgA) with staphylococcal superantigen-like 7 (SSL7) decoy protein and leukocyte IgA receptor

Bruce D. Wines, Paul A. Ramsland, Halina M. Trist, Sandra Gardam, Robert Brink, John D. Fraser, P. Mark Hogarth

Research output: Contribution to journalArticleResearchpeer-review

10 Citations (Scopus)


Host survival depends on an effective immune system and pathogen survival on the effectiveness of immune evasion mechanisms. Staphylococcus aureus utilizes a number of molecules to modulate host immunity, including the SSL family of which SSL7 binds IgA and inhibits Fcα receptor I (FcαRI)-mediated function. Other Gram-positive bacterial pathogens produce IgA binding proteins, which, similar to SSL7, also bind the Fc at the CH2/CH3 interface (the junction between constant domains 2 and 3 of the heavy chain). The opposing activities of the host FcαRI-IgA receptor ligand pair and the pathogen decoy proteins select for host and pathogen variants, which exert stronger protection or evasion, respectively. Curiously, mouse but not rat IgA contains a putative N-linked glycosylation site in the center of this host receptor and pathogen-binding site. Here, we demonstrate that this site is glycosylated and that the effect of amino acid changes and glycosylation of the CH2/CH3 interface inhibits interaction with the pathogen IgA binding protein SSL7, while maintaining binding of pIgR, essential to the biosynthesis and transport of SIgA.

Original languageEnglish
Pages (from-to)33118-33124
Number of pages7
JournalThe Journal of Biological Chemistry
Issue number38
Publication statusPublished - 23 Sep 2011
Externally publishedYes

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