title: LPS augments human B-cell differentiation by direct stimulation of PWM-responsive B cells.
abstract: Bacterial lipopolysaccharide (LPS) augments production of IgM and IgG by two- to seven-fold in cultures of peripheral blood lymphocytes (PBL) stimulated by pokeweed mitogen (PWM), but only if monocytes are rigorously depleted. When PBL were separated into adherent cell (AC), B-cell-enriched, and T-cell-enriched fractions, pulsed with LPS, and recombined in culture with PWM, increased generation of plasma cells was seen only in cultures containing LPS-treated B cells. This effect of LPS appears to be independent of soluble factors. Supernatants from LPS-stimulated B cells or AC did not consistently increase PWM responses when cultured with fresh B cells in the presence of polymyxin B. Furthermore, pulsing of B cells with purified interleukin 1 from two different commercial sources failed to augment PWM-induced differentiation. When B cells were depleted of surface IgD (sIgD)-bearing cells by panning, no effect on LPS-mediated augmentation of PWM-driven differentiation was seen. B cells were also fractionated by rosetting with mouse erythrocytes. Treatment of BMR+ cells with LPS did not induce them to respond to PWM, while treatment of BMR- cells with LPS augmented generation of plasma cells. These results indicate that LPS acts directly to augment differentiation of PWM-responsive B cells, rather than recruiting sIgD+, BMR+ cells to become PWM responsive.
mesh_terms: D000328:Adult; D000921:Antibody-Producing Cells / Q000187:drug effects; D001402:B-Lymphocytes / Q000145:classification* / Q000166:cytology / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002469:Cell Separation; D002478:Cells, Cultured; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D010950:Plasma Cells / Q000187:drug effects; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D013268:Stimulation, Chemical
chemical_list: D008070:Lipopolysaccharides; D011043:Pokeweed Mitogens; D011947:Receptors, Antigen, B-Cell