Production and characterization of a unique monoclonal antibody against human B cells (33.2.1).
A monoclonal antibody specific for a polymorphic antigen on human B cells (33.2.1) was produced and characterized. By flow cytometry, 33.2.1 was found to react with peripheral blood B cells, monocytes, and Epstein-Barr virus (EBV)-transformed B-cell lines, but not with peripheral blood T cells, mitogen-activated T cells, or allo- or autoactivated T cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that 33.2.1 recognizes a noncovalently bound bimolecular complex composed of an alpha chain of about 32 kDa and a beta chain of about 28 kDa. The failure of anti-HLA-DR, anti-Leu-10, and anti-HLA-DC1 to remove the 33.2.1 antigen by sequential immunoprecipitation suggests that 33.2.1 recognizes a distinct molecule rather than a different epitope on either HLA-DR or DS/DC/MB. In T-cell-independent B-cell activation systems, preincubation with 33.2.1 markedly inhibited RNA and DNA synthesis as well as polyclonal Ig production. In contrast, anti-HLA-DR was inhibitory only when it was present throughout the culture, but not when it was used for preincubation. Anti-Leu-10 led to only moderate inhibition. These results suggest that 33.2.1 recognizes a unique Ia-like antigen critical for B-cell activation.
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D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001667:Binding, Competitive; D004247:DNA / Q000096:biosynthesis; D000939:Epitopes / Q000276:immunology; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D012313:RNA / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000939:Epitopes; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007136:Immunoglobulins; D012313:RNA; D004247:DNA