Human B cell differentiation. III. Enhancing effect of monoclonal anti-immunoglobulin D antibody on pokeweed mitogen-induced plasma cell differentiation.
The effects of monoclonal anti-delta antibodies on pokeweed mitogen (PWM) responses of blood mononuclear cells (MNC) were studied. Treatment with anti-delta antibody enhanced both B cell proliferation and plasma cell differentiation, which are T cell-dependent responses. The anti-delta enhancement of plasma cell differentiation, predominantly of IgM plasma cells, was surprising because PWM-responsive subpopulations of B cells have been shown to lack IgD and their plasma cell differentiation is easily and selectively suppressed by anti-mu, -gamma and -alpha antibodies. Treatment of MNC with monoclonal anti-delta antibody enhanced the number of IgM plasma cells induced by PWM stimulation by approximately threefold. The degree of enhancement was dependent upon the concentration of anti-delta antibody, and the F(ab')2 fragments were effective. Maximal enhancement was obtained either when MNC were preincubated with anti-delta antibody for 1 day before PWM stimulation or when anti-delta antibody was added with PWM at the beginning of 7-day cultures. Anti-delta antibody had little or no effect when added 1 to 3 days after the initiation of PWM stimulated cultures. Anti-delta treatment overnight induced a population of small IgM+IgD+ B cells to enlarge and converted them from poor to good PWM responders. The results are discussed in the context of a model which proposed that differentiation of both immature and preactivated mature IgD- cells can be inhibited by signals generated via surface immunoglobulin cross-linkage, whereas this stimulus enhances differentiation of the intermediate IgD+IgM+ B cells.
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002469:Cell Separation; D006801:Humans; D007072:Immunoglobulin D / Q000276:immunology*; D007075:Immunoglobulin M / Q000032:analysis; D010950:Plasma Cells / Q000276:immunology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D007072:Immunoglobulin D; D007075:Immunoglobulin M; D011043:Pokeweed Mitogens; D011947:Receptors, Antigen, B-Cell