Activation of murine B lymphocytes by anti-immunoglobulin is an inductive signal leading to immunoglobulin secretion.
Cultures of isolated mouse splenic B lymphocytes activated by the divalent F(ab')2 fragment of purified rabbit anti-mouse Fab or class-specific anti-mouse IgM antibodies can be driven on to high rate Ig secretion by the addition of the supernatant fluid of a 24-h culture of concanavalin A-activated spleen cells (SN). The polyclonal antibody response to anti-Ig pus SN is comparable in magnitude with the lipopolysaccharide response as measured in a reverse plaque assay. The addition of SN can be delayed for 24 h after addition of anti-Ig without changing the kinetics of the response. Addition at 48 h delays the response by 24 h. The response to F(ab')2 anti-Fab plus SN is sensitive to Fc-dependent inhibition because intact anti-Fab antibodies inhibit strongly at relatively low concentrations. The monovalent Fab' fragment fails to induce Ig secretion, indicating that cross-linkage of surface immunoglobulin is required. Although the production of active SN is T cell dependent, the response to anti-Ig plus SN is T independent. These findings are interpreted as a polyclonal model of a thymus-dependent antibody response.                                                                                 X
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure; D002478:Cells, Cultured; D005260:Female; D007141:Immunoglobulin Fc Fragments / Q000276:immunology; D007136:Immunoglobulins / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D011817:Rabbits; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors
D000888:Antibodies, Anti-Idiotypic; D007141:Immunoglobulin Fc Fragments; D007136:Immunoglobulins; D008070:Lipopolysaccharides