title: Staphylococcal protein a deletes B-1a and marginal zone B lymphocytes expressing human immunoglobulins: an immune evasion mechanism.
abstract: Protein A (SpA) of Staphylococcus aureus is endowed with the capacity to interact with the H chain variable region (V(H)) of human Abs and to target >40% of B lymphocytes. To investigate whether this property represents a virulence factor and to determine the in vivo consequences of the confrontation of SpA with B lymphocytes, we used transgenic mice expressing fully human Abs. We found that administration of soluble SpA reduces B-1a lymphocytes of the peritoneal cavity and marginal zone B lymphocytes of the spleen, resulting in a markedly deficient type 2 humoral response. Single-cell PCR analysis and sequencing of the Ab V(H) gene repertoire revealed a significant reduction of V(H)3+ marginal zone B cells. Since the two B lymphocyte subsets targeted are involved in innate immune functions, our data suggest that crippling of humoral immunity by S. aureus represents an immune evasion mechanism that may aggravate recurrent infections.
authors.affiliation: Institut National de Santé et de Recherche Médicale Unite 430, Immunopathologie Humaine, Paris, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Viau
authors.forename: Nancy S
authors.initials: NS
authors.lastname: Longo
authors.forename: Peter E
authors.initials: PE
authors.lastname: Lipsky
authors.forename: Moncef
authors.initials: M
authors.lastname: Zouali
mesh_terms: D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D010529:Peritoneal Cavity / Q000166:cytology; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013205:Staphylococcal Protein A / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology / Q000472:pathogenicity*
chemical_list: D007135:Immunoglobulin Variable Region; D011994:Recombinant Proteins; D013205:Staphylococcal Protein A