Publications & Reports

Interaction of Human, Rat, and Mouse Immunoglobulin A (IgA) with Staphylococcal Superantigen-like 7 (SSL7) Decoy Protein and Leukocyte IgA Receptor.

Wines BD, Ramsland PA, Trist HM, Gardam S, Brink R, Fraser JD, Hogarth PM
From the Centre for Immunology, The Burnet Institute, 85 Commercial Road, Melbourne 3004, Australia.


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 Fcalpha receptor I (FcalphaRI)-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 FcalphaRI-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.


  • Journal: The Journal of Biological Chemistry
  • Published: 23/09/2011
  • Volume: 286
  • Issue: 38
  • Pagination: 33118-33124