title: Regulation of antibody response in vitro. IX. Induction of secondary anti-hapten IgG antibody response by anti-immunoglobulin and enhancing soluble factor.
abstract: Attempts were made to induce antibody response of hapten-primed cells by stimulation with anti-immunoglobulin (Ig) antibody and cellfree supernatant (CFS) which contained nonspecific enhancing factor. Mesenteric lymph node cells were obtained from rabbits which were primed with dinitrophenylated ragweed antigen (DNP-Rag), and the primed cells were incubated in vitro with either anti-rabbit gamma-chain or anti-Fab antibody for 24 hr. After washing, the cells were cultured in CFS which was obtained from the culture of DNP-Ascaris (DNP-Asc)-primed lymph node cells with free carrier (Asc). The results showed that hapten-primed cells were triggered for IgG anti-DNP antibody response by the two reagents, i.e., anti-Ig antibody and CFS, both which did not share any antigenic specificity with the priming antigen (DNP-Rag). Neither anti-Ig alone nor CFS alone induced anti-hapten antibody response. Anti-Ig and CFS triggered not only hapten-primed B cells but also the other IgG-bearing (B) cells for IgG synthesis. Lymph node cells of umprimed animals were activated for IgG synthesis by the stimulation with anti-Ig followed by culture in CFS. Evidence was obtained that anti-Ig antibody has to be divalent for the activation of B cells. Stimulation of DNP-primed cells with the F(ab')2 fragment of the antibody and CFS-induced anti-hapten antibody response, whereas the Fag' fragment of the anti-Ig plus CFS failed to do so. The results suggested that bridging of cell-surface Ig receptors by multivalent ligand is the initial step of B cell activation. Another evidence for the activation of hapten-primed B cells by anti-Ig was obtained by supplemental immunization of DNP-Asc-primed animals with the Fc fragment of goat IgG. Stimulation of mesenteric lymph node cells from these animals with goat anti-rabbit-Ig alone (no CFS) resulted in the formation of anti-DNP IgG antibody. The results indicated that lymphocytes primed for goat IgG collaborated with DNP-primed IgG-B cells when the lymph node cells were stimulated with goat anti-Ig.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D000917:Antibody Formation; D001200:Ascaris / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology; D006041:Goats / Q000276:immunology; D006168:Guinea Pigs / Q000276:immunology; D006241:Haptens; D006433:Hemocyanins / Q000276:immunology; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G / Q000096:biosynthesis*; D008974:Mollusca / Q000276:immunology; D009578:Nitrobenzenes / Q000276:immunology; D011058:Pollen; D011817:Rabbits
chemical_list: D000888:Antibodies, Anti-Idiotypic; D006241:Haptens; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D009578:Nitrobenzenes; D006433:Hemocyanins