B-cell stimulatory factor 1 activates resting B cells.
B-cell stimulatory factor 1 (BSF-1) is a T-cell-derived lymphokine that acts together with low concentrations of anti-IgM antibodies to stimulate resting B cells to enter the G1 phase of the cell cycle and to synthesize DNA. We show here that supernatants from EL-4 cells, rich in BSF-1 activity, and BSF-1 purified by high-pressure liquid chromatography (HPLC-BSF-1) act on resting B cells, in the absence of anti-IgM antibodies, to prepare them to respond to anti-IgM and BSF-1. A 24-hour preculture with BSF-1 speeds the entry into S phase of B cells subsequently cultured with anti-IgM and BSF-1 by approximately equal to 12 hours and causes substantial increase in cell volume of all resting B cells. Both of these effects, stimulated either by EL-4 supernatants or by HPLC-BSF-1, are inhibited by a monoclonal anti-BSF-1 antibody. These results lead us to propose that BSF-1 should be regarded as a B-cell activation factor.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D005260:Female; D006133:Growth Substances / Q000494:pharmacology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D066298:In Vitro Techniques; D015847:Interleukin-4; D007399:Interphase; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C
D000888:Antibodies, Anti-Idiotypic; D006133:Growth Substances; D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M; D008222:Lymphokines; D015847:Interleukin-4