title: Induction of phorbol ester responsiveness in conventional B cells after activation via surface Ig.
abstract: The signals required to induce S phase entry in murine splenic B cells were found to be altered by prolonged treatment with low doses of anti-Ig antibody. Whereas fresh splenic B cells are stimulated by the combination of a phorbol ester protein kinase C agonist plus a calcium ionophore, anti-Ig-treated splenic B cells were stimulated by phorbol ester alone, in the absence of a comitogen. The majority of these phorbol ester responsive B cells expressed CD5. The phorbol ester responses of anti-Ig-treated splenic B cells paralleled those previously reported for untreated peritoneal CD5+ B cells in a number of respects: responses were not idiosyncratic to phorbol esters but occurred with nonphorbol protein kinase C agonists; phorbol ester responses were enhanced by IL-4; and, phorbol ester responses occurred rapidly and were greater at 24 than at 48 h. However, the effect of agents that act to raise intracellular levels of cAMP distinguished between anti-Ig-treated splenic B cells and untreated peritoneal B cells in that the phorbol ester responses of the former were enhanced whereas the responses of the latter were inhibited. The present results add a functional dimension to the phenotypic similarity between splenic B cells treated with anti-Ig and resident peritoneal B cells that constitutively express CD5; however, some differences in behavior were noted.
authors.affiliation: Department of Medicine, Boston University Medical Center, MA 02118.
authors.forename: T L
authors.initials: TL
authors.lastname: Rothstein
authors.forename: D L
authors.initials: DL
authors.lastname: Kolber
authors.forename: T P
authors.initials: TP
authors.lastname: Murphy
authors.forename: D P
authors.initials: DP
authors.lastname: Cohen
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000502:physiology*; D018956:CD5 Antigens; D002453:Cell Cycle / Q000187:drug effects; D000242:Cyclic AMP / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004306:Dose-Response Relationship, Immunologic; D015847:Interleukin-4 / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D010703:Phorbol Esters / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D013997:Time Factors
chemical_list: D015703:Antigens, CD; D018956:CD5 Antigens; D010703:Phorbol Esters; D011947:Receptors, Antigen, B-Cell; D015847:Interleukin-4; D000242:Cyclic AMP; D011493:Protein Kinase C