title: Effect of anti-delta antibodies on clonal expansion and maturation of B lymphocytes.
abstract: The effect of a monoclonal anti-delta antibody on the in vitro B cell response to the B cell mitogen lipopolysaccharide (LPS) has been studied. Titration of anti-delta antibody in mass cultures stimulated by LPS resulted in a dose-dependent reduction of thymidine incorporation. IgM and IgG plaque forming cell (PFC) responses were poorly affected at high concentration, and slightly increased at low concentrations of anti-delta antibody. By limiting dilution analysis it was shown that anti-delta antibody inhibit 30-50% of LPS-reactive B cells to grow as IgM secreting clones, while increasing the average size of clones that grew in the presence of anti-delta as compared to control cultures. Anti-delta also results in increased frequencies of IgG secreting clones. By immunofluorescence it was possible to show the presence of a higher relative number of cells containing immunoglobulin as an effect of anti-delta antibodies. Observations made at early times of culture indicate that the cells that do not proliferate in the presence of anti-delta undergo an early maturation to secretion. Experiments performed on LPS blasts suggest that the effects of anti-delta on cell proliferation require the presence of antibodies at early times in the response, while the effects on maturation can be manifested during clonal development. The relevance of membrane IgD and of the IgM-to-IgD ratio in the maintenance versus exhaustion of the clone is discussed.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D002999:Clone Cells / Q000276:immunology; D004305:Dose-Response Relationship, Drug; D007072:Immunoglobulin D / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D051379:Mice
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008070:Lipopolysaccharides