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Role of Protein A in the Evasion of Host Adaptive Immune Responses by Staphylococcus aureus

Heritable defects in human B cell/antibody development are not associated with increased susceptibility to Staphylococcus aureus infection. Protein A (SpA), a surface molecule of S. aureus, binds the Fcγ domain of immunoglobulin (Ig) and cross-links the Fab domain of V(H)3-type B cell receptors (IgM...

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Detalles Bibliográficos
Autores principales: Falugi, Fabiana, Kim, Hwan Keun, Missiakas, Dominique M., Schneewind, Olaf
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society of Microbiology 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3760252/
https://www.ncbi.nlm.nih.gov/pubmed/23982075
http://dx.doi.org/10.1128/mBio.00575-13
Descripción
Sumario:Heritable defects in human B cell/antibody development are not associated with increased susceptibility to Staphylococcus aureus infection. Protein A (SpA), a surface molecule of S. aureus, binds the Fcγ domain of immunoglobulin (Ig) and cross-links the Fab domain of V(H)3-type B cell receptors (IgM). Here we generated S. aureus spa variants harboring amino acid substitutions at four key residues in each of the five Ig-binding domains of SpA. Wild-type S. aureus required SpA binding to Ig to resist phagocytosis and SpA-mediated B cell receptor cross-linking to block antibody development in mice. The spa(KKAA) mutant, which cannot bind Ig or IgM, was phagocytosed and elicited B cell responses to key virulence antigens that protected animals against lethal S. aureus challenge. The immune evasive attributes of S. aureus SpA were abolished in µMT mice lacking mature B cells and antibodies. Thus, while wild-type S. aureus escapes host immune surveillance, the spa(KKAA) variant elicits adaptive responses that protect against recurrent infection.