B cell stimulatory factor 1 (BSF-1) prepares resting B cells to enter S phase in response to anti-IgM and lipopolysaccharide.
BSF-1 prepares resting BALB/c, DBA/2, and BDF1 B cells to enter S phase more promptly in response to subsequent culture with anti-IgM-based stimulants. It prepares DBA/2 and BDF1 B cells to respond to LPS, but its preparative effect for LPS responses of BALB/c B cells is both inconstant and meager. Preparation mediated by BSF-1 requires extended contact of B cells with the stimulant for full effect. Half-maximal preparation requires approximately 12 h of contact, as judged by delayed addition of BSF-1 or by inhibition of BSF-1 action with anti-BSF-1 mAbs. BSF-1 preparative action on resting DBA/2 B cells is mimicked by anti-Lyb-2.1 antibody. B cell blasts prepared by culture with BSF-1 and anti-IgM show modest responses to high concentrations of BSF-1; large B cells directly isolated from the spleen are not stimulated to enter S phase by BSF-1. These results lead us to conclude that BSF-1 functions principally as an activation factor for resting B cells.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology*; D000950:Antigens, Ly / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000502:physiology; D002470:Cell Survival; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006133:Growth Substances / Q000494:pharmacology*; D007075:Immunoglobulin M / Q000502:physiology*; D015847:Interleukin-4; D007399:Interphase; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D013997:Time Factors
D000888:Antibodies, Anti-Idiotypic; D000950:Antigens, Ly; D006133:Growth Substances; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D008222:Lymphokines; C044203:anti-IgM; D015847:Interleukin-4