title: Polyclonal activation of primed rat B cells.
abstract: In recent years, murine and human virgin B lymphocytes have been used to examine the steps necessary for polyclonal activation. In these models mitogens are used in conjunction with lymphokines to determine which signals are responsible for regulating B-cell triggering, proliferation, and differentiation. While progress has been made in understanding these events as they occur in virgin B cells, very little evidence exists to suggest whether these models of activation also apply to the memory B-cell population. In this report we have described an antigen-specific, secondary in vitro immune response using cells isolated from lymph nodes draining the site of antigen injection. Unfractionated cells, B cells, and size-fractionated cells from dinitrophenyl-keyhole limpet hemocyanin (DNP-KLH)-primed rats were challenged in vitro with DNP-KLH, lipopolysaccharide plus dextran sulfate (LPS/DxS), and T-cell factors. We have consistently found, under all these conditions, that antigen challenge of primed cells results in the production of DNP-specific IgG antibody while stimulation with LPS/DxS plus T-cell factors results only in the polyclonal activation of virgin B cells; no antigen-specific IgG secretion is seen. This suggests that acquisition of memory status is associated with a loss in responsiveness to LPS/DxS-induced differentiation.
mesh_terms: D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D016264:Dextran Sulfate; D003911:Dextrans / Q000494:pharmacology; D005260:Female; D006433:Hemocyanins / Q000276:immunology; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007156:Immunologic Memory; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D051381:Rats
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface; D003911:Dextrans; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D006433:Hemocyanins; D016264:Dextran Sulfate; C032808:keyhole-limpet hemocyanin