Detection and functional studies of p60-65 (Tac antigen) on activated human B cells.
A monoclonal antibody, AT-1, is shown to precipitate a p60-65 molecule identical to the Tac antigen. With AT-1, the expression of IL-2 receptors by normal activated human B cells from peripheral blood and tonsils is documented by biosynthetic and immunofluorescence studies. AT-1 precipitated a p60-65 protein from [35S]methionine-labeled activated B cells, similar to that from activated T cells. The interleukin 2 (IL-2) receptor appeared shortly after activation with anti-IgM and B cell-stimulatory factor(s). Its expression reached its peak at 60-72 h with approximately 50% of the B blasts stained by AT-1. Other modes of activation of B cells, by T cell-independent, formalin-treated staphylococci and Epstein-Barr virus, and by T cell-dependent pokeweed mitogen, also induced IL-2 receptor expression. The functional significance of this finding was investigated using recombinant IL-2 (rIL-2). While rIL-2 did not induce resting B cells to proliferate in the presence of anti-IgM, it induced activated B cells to proliferate in the absence of other factors. On the other hand, rIL-2 did not induce the differentiation of these activated B lymphocytes. These data suggest that IL-2 may play a significant role in B cell activation.
D000818:Animals; D000911:Antibodies, Monoclonal; D000954:Antigens, Surface / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation; D051379:Mice; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007376:Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7