title: Requirement for accessory cells in the antibody response to T cell-independent antigens in vitro.
abstract: The antibody responses of mouse spleen cells in vitro to three thymus-independent (TI) antigens namely, polymeric flagellin (POL) of Salmonella adelaide, DNP-Ficoll and "soluble" sheep erythrocyte (SRBC) antigen, were found to be dependent on adherent accessory cells (A cells) but to a lesser degree than the response to intact SRBC. Evidence for this comes from selective depletion of A cells from spleen cells and reconstitution with A cell-rich populations. Thus, depletion of A cells by adherence on glass resulted in abolition of the response to SRBC leaving the response to POL intact. More thorough removal of A cells by treatment with carbonyl iron powder was required for appreciable reduction of the responses to POL, DNP-Ficoll and "soluble" SRBC. This reduction in responsiveness was not due to poor cell survival after A cell depletion or to the loss of immunocompetent cells since 1) the recoveries of viable cells in all cultures were similar; 2) the contents of theta- and Ig-bearing cells and tritium-labeled POL-binding cells were unaltered after carbonyl iron treatment, and 3) responsiveness was fully restored by the addition of irradiated and anti-theta-treated A cells from the peritoneal cavity or the spleen. Hence, the hitherto A cell independence of TI antigens on which some theories of B cell activation are based is a result of inadequate depletion procedures, and the minimal model for B cell activation must take into account two cell types: B cells and A cells.
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001202:Ascitic Fluid / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D002448:Cell Adhesion; D002469:Cell Separation; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D005362:Ficoll / Q000276:immunology; D005408:Flagellin / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D008297:Male; D008623:Mercaptoethanol / Q000494:pharmacology; D051379:Mice; D008808:Mice, Inbred CBA; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D005408:Flagellin; D005362:Ficoll; D008623:Mercaptoethanol