Sequential effect of a high molecular weight B cell growth factor and of interleukin 2 on activated human B cells.
A high m.w. B cell growth factor (50,000 BCGF) prepared from lectin-activated human peripheral blood lymphocyte culture supernatants acts only on B cells preactivated by a first signal. This first signal can be delivered in vitro (with anti-mu antibody (Ab)) or in vivo. Upon costimulation with anti-mu Ab the 50,000 BCGF induces an early and transient proliferative response, whereas the response to interleukin 2 (IL-2) develops more progressively. To determine the respective targets of the 50,000 BCGF and of IL-2, B cells were activated with anti-mu Ab and separated according to the expression of the IL-2 receptor (cluster designation (CD)25 antigen). CD25+ B cells do not respond to the 50,000 BCGF and do not acquire this responsiveness after an additional culture with IL-2. CD25- B cells respond to the 50,000 BCGF and not to IL-2. However, when CD25- B cells are cultured for 3 days with the 50,000 BCGF they become responsive to IL-2. These results demonstrate a pathway of B cell activation based on the ordered and sequential action of anti-mu Ab, the 50,000 BCGF, and IL-2.
D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D001402:B-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D002455:Cell Division / Q000187:drug effects; D004357:Drug Synergism; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4; D007378:Interleukins / Q000494:pharmacology*; D007700:Kinetics; D008213:Lymphocyte Activation; D008970:Molecular Weight; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2
D000888:Antibodies, Anti-Idiotypic; D007075:Immunoglobulin M; D007376:Interleukin-2; D007378:Interleukins; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; C044203:anti-IgM; D015847:Interleukin-4