Major histocompatibility complex-restricted, polyclonal B cell responses resulting from helper T cell recognition of antiimmunoglobulin presented by small B lymphocytes.
Anti-Ig has been widely used as a model for antigen receptor-mediated B cell activation. B cells activated with mitogenic concentrations of anti-Ig (approximately 10 micrograms/ml) become responsive to a set of T cell-derived, antigen-nonspecific helper factors that enable the B cells to proliferate, and, in some cases, mature to Ig secretion. In the present experiments, we show that anti-Ig can also be used as a model for major histocompatibility complex (MHC)-restricted, antigen-specific T-B cell collaboration. We used murine helper T cell lines and T cell hybridomas specific for a protein antigen, the F(ab')2 fragment of normal rabbit IgG. Small B cells are very efficient at presenting rabbit anti-IgM or rabbit anti-IgD to these rabbit Ig-specific T cell lines and hybridomas, and the responding (initially) small B cells, appear to be the only antigen-presenting cells required. Efficient presentation depends upon binding of rabbit antibody to mIg on the B cell surface. MHC-restricted recognition of rabbit Ig determinants on the B cell surface results in a polyclonal B cell response. This response is qualitatively different from the well-studied response to blastogenic concentrations of anti-Ig plus stable, T cell-derived helper factors, since it (a) requires 1,000-fold lower concentrations of anti-Ig, (b) involves helper T cell functions other than, or in addition to, the local production of the same stable helper factors, and (c) is largely MHC-restricted at the T-B cell level.
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D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000918:Antibody Specificity; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002460:Cell Line; D006183:H-2 Antigens / Q000235:genetics; D006825:Hybridomas / Q000276:immunology; D007399:Interphase; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D007959:Lymphocyte Culture Test, Mixed; D008285:Major Histocompatibility Complex; D051379:Mice; D011817:Rabbits; D013601:T-Lymphocytes / Q000276:immunology
D000888:Antibodies, Anti-Idiotypic; D006183:H-2 Antigens