title: In vitro effects of cyclosporin A on human B-cell responses.
abstract: The in vitro effects of cyclosporin A (CsA) on T-cell-dependent and T-cell-independent mitogen responses of human B cells were studied. T-cell-dependent, pokeweed mitogen (PWM)-induced B-cell proliferation and B-cell differentiation to Ig-secreting cells were significantly inhibited by CsA, when purified B cells were cultured with T-cell helper factor containing supernatants instead of T cells. This indicates that the inhibitory effect of CsA on T-cell-dependent, PWM-induced B-cell proliferation and differentiation is not exclusively due to direct effects on helper T cells. B-cell proliferations induced by anti-IgM antibodies and by Staphylococcus aureus bacteria were also found to be sensitive to CsA. Since both types of reactions are T-cell-independent, the concept that responses of human B cells can also be affected by CsA in ways that seem to be independent of the well-documented direct effects of CsA on T cells is further supported. This seems not to be a general phenomenon, however. Epstein-Barr-virus-induced activation of human B cells, as reported previously and also observed by us, is completely insensitive to CsA. It seems, therefore, that certain B-cell activation mechanisms are sensitive to CsA while others remain unaltered. The difference between these two reaction patterns cannot be exclusively explained by a T-cell dependence or T-cell independence of these responses. CsA effects on certain functional B-cell subsets or interference with accessory cell mechanisms might be responsible.
mesh_terms: D000921:Antibody-Producing Cells / Q000187:drug effects; D001402:B-Lymphocytes / Q000187:drug effects*; D003524:Cyclosporins / Q000494:pharmacology*; D006801:Humans; D007165:Immunosuppression Therapy; D008213:Lymphocyte Activation / Q000187:drug effects*; D011043:Pokeweed Mitogens / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D003524:Cyclosporins; D011043:Pokeweed Mitogens