Peritoneal B cells respond to phorbol esters in the absence of co-mitogen.
B cells obtained by irrigation of the peritoneal cavity differ from splenic B cells in signaling requirements for the initiation of DNA synthesis. Splenic B cells are stimulated to enter S phase by phorbol esters in conjunction with a second signal provided by calcium ionophore; however, splenic B cells are not stimulated by phorbol ester alone. In contrast, peritoneal B cells from NZB and BALB/c mice were stimulated to incorporate tritiated thymidine by each of the phorbol esters, PMA and phorbol dibutyrate, acting alone. Stimulation of peritoneal B cells was apparent when cells were cultured at lower than usual cell densities, and responses were unaffected by coculture with splenic B cells. Responding cells adhered to plastic petri dishes coated with anti-mouse IgM antibody, but were not completely removed by treatment with anti-Ly-1.2 antibody plus C. These results indicate that phorbol esters constitute a complete signal that stimulates some peritoneal B cells to enter S phase.
Rothstein
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Evans Memorial Department of Clinical Research, Boston University Medical Center, MA 02118.
Kolber
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D000818:Animals; D000950:Antigens, Ly / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D007108:Immune Tolerance; D007075:Immunoglobulin M / Q000032:analysis; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D008814:Mice, Inbred NZB; D008934:Mitogens / Q000494:pharmacology; D010529:Peritoneal Cavity / Q000166:cytology* / Q000276:immunology; D010703:Phorbol Esters / Q000494:pharmacology*; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D013154:Spleen / Q000166:cytology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000950:Antigens, Ly; D007075:Immunoglobulin M; D008934:Mitogens; D010703:Phorbol Esters; D011947:Receptors, Antigen, B-Cell