title: Expression of VHIII-associated cross-reactive idiotype on human B lymphocytes. Association with staphylococcal protein A binding and Staphylococcus aureus Cowan I stimulation.
abstract: It has been demonstrated that staphylococcal protein A (SPA) has an "alternative" binding site with specificity for human Ig H chain V region of the VHIII subgroup. Because the major mitogenic component of Staphylococcus aureus Cowan I (SAC) is SPA, it is possible that SAC stimulates a subpopulation of B cells expressing Ig of the VHIII H chain subgroup. In the present study, we have investigated further the relationship between SPA binding and the expression of VHI- or VHIII-associated cross-reactive idiotype (CRI) on the surface of tonsillar B lymphocytes enriched for the expression or nonexpression of the CRI, and we examined the Ig secreted by cell lines established from these populations of B cells by EBV transformation. The VHIII CRI (D12)-enriched population yielded 21 cell lines, with 67% of them secreting SPA-reactive Ig; in contrast, only 6% (1 of 16) of VHI CRI-expressing lines secreted SPA-reactive Ig. The CRI-negative B cell population yielded 54 cell lines, of which 20% secreted SPA-reactive Ig, as might be anticipated because a majority of VHIII Ig+ B cells will be CRI-. SAC stimulation of CRI+ and CRI- populations showed preferential stimulation of the D12 population. These data support the proposal that SAC stimulation of human B cells is mediated through binding of SPA by its alternative binding site to IgV regions of the VHIII subgroup.
authors.affiliation: Department of Immunology, Medical School, University of Birmingham, United Kingdom.
authors.forename: F
authors.initials: F
authors.lastname: Shokri
authors.forename: R A
authors.initials: RA
authors.lastname: Mageed
authors.forename: B R
authors.initials: BR
authors.lastname: Maziak
authors.forename: R
authors.initials: R
authors.lastname: Jefferis
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001665:Binding Sites; D002472:Cell Transformation, Viral; D003429:Cross Reactions; D004854:Herpesvirus 4, Human; D006801:Humans; D007130:Immunoglobulin Idiotypes / Q000032:analysis* / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000032:analysis*; D008213:Lymphocyte Activation; D051379:Mice; D013205:Staphylococcal Protein A / Q000378:metabolism* / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D013205:Staphylococcal Protein A; D013755:Tetradecanoylphorbol Acetate