B-cell growth factor (B-cell growth factor I or B-cell-stimulating factor, provisional 1) is a differentiation factor for resting B cells and may not induce cell growth.
B-cell growth factor I [BCGF I or B-cell-stimulating factor, provisional 1 (BSFp1)] has been defined as a T-cell-derived lymphokine that acts as a co-stimulator of polyclonal B-cell growth in B cells cultured with anti-mu, anti-delta, or anti-Ig. Based on a number of studies it has been suggested that anti-Ig induces cell enlargement, entry into the G1 phase of the cell cycle, and expression of receptors for BSFp1. BSFp1 then induces entry of the cells into S phase. By adding BSFp1 prior to anti-Ig, we have found evidence that BSFp1 renders cells susceptible to anti-Ig-mediated entry of cells into G2/S phase. In contrast, if cells are first treated with anti-Ig, washed, and then cultured with BSFp1, they do not enter S phase. Taken together, these results suggest that BSFp1 acts on the resting B cells not as a growth factor but rather as a lymphokine that prepares cells for anti-Ig-mediated activation. Taken together with previous reports that BSFp1 induces increased expression of Ia antigens on resting B cells, these studies suggest that BSFp1 may be a differentiation factor rather than a growth factor and that it acts on resting B cells.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D006133:Growth Substances / Q000494:pharmacology*; D007136:Immunoglobulins / Q000276:immunology; D015847:Interleukin-4; D007399:Interphase; D008222:Lymphokines / Q000494:pharmacology*; D051379:Mice
D000888:Antibodies, Anti-Idiotypic; D006133:Growth Substances; D007136:Immunoglobulins; D008222:Lymphokines; D015847:Interleukin-4