Expression and function of an early activation marker restricted to human B cells.
A B cell-specific monoclonal antibody (anti-Ba) was prepared. In two-color FACS analysis the anti-Ba reacted with a subpopulation of Ig+ or B1+ cells obtained from tonsils, but did not react with most B1+ cells derived from PBL. Activation of B cells from PBL with TPA or anti-mu induced Ba expression and the addition of PHA-conditioned supernatant with anti-mu-enhanced Ba expression. Other B cell activators, such as Staphylococcus aureus Cowan I (Staph-A) or PWM plus T cells, could induce Ba expression. Ba expression was observed 6 hr after stimulation and reached a peak level at 72 hr. Ba expression was strictly restricted to B cells. H-7, a specific inhibitor of protein kinase C (C-kinase), displayed a dose-dependent inhibitory effect on Ba expression, showing dependency on C-kinase for Ba expression. Anti-Ba inhibited B cell proliferation induced by anti-mu and B-BCGF distinct from BSF-1. The results presented in this study suggest that the Ba antigen on B cells may be comparable to the Tac antigen on T cells.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D000937:Antigen-Antibody Reactions; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology* / Q000378:metabolism; D001667:Binding, Competitive; D004789:Enzyme Activation; D005260:Female; D006133:Growth Substances / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D006801:Humans; D015847:Interleukin-4; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000032:analysis* / Q000378:metabolism / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D014066:Palatine Tonsil / Q000166:cytology; D010641:Phenotype; D011493:Protein Kinase C / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
D000911:Antibodies, Monoclonal; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface; D006133:Growth Substances; D008222:Lymphokines; D011947:Receptors, Antigen, B-Cell; D015847:Interleukin-4; D011493:Protein Kinase C