Increased expression of Ia antigens on resting B cells: an additional role for B-cell growth factor.
The present studies demonstrate that both T-cell-derived supernatants containing B-cell growth factor (BCGF or BSF) and a partially purified preparation of the B-cell growth factor (BSF-p1) induce an increase in the expression of IA and IE-encoded antigens on small resting B cells. This increase is detectable by 6-8 hr after initiation of culture and is relatively selective, since levels of surface immunoglobulin and H-2 antigens do not increase to the same extent. Although interferon-gamma induces increased expression of Ia antigens on macrophages and dividing neoplastic B cells, it does not induce an increase in the expression of Ia antigens on resting B cells. These results demonstrate that BSF-p1 may play two roles: (i) it acts on resting B cells to increase the levels of Ia antigen expression; and (ii) it sustains the growth of B cells that have been previously activated with mitogens, antigens, or anti-Ig.
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D005260:Female; D005802:Genes, MHC Class II; D006133:Growth Substances / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D015847:Interleukin-4; D007700:Kinetics; D008222:Lymphokines / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C
D000954:Antigens, Surface; D006133:Growth Substances; D000949:Histocompatibility Antigens Class II; D008222:Lymphokines; D015847:Interleukin-4