title: Feedback suppression of the immune response in vitro. I. Activity of antigen-stimulated B cells.
abstract: Feedback regulation of the primary humoral immune response to sheep erythrocytes (SRBC) was studied in vitro. Whole spleen cells or spleen cell subpopulations were incubated with antigen for 4 d under Mishell-Dutton conditions (education) and the surviving cells tested for regulatory activity in fresh anti-SRBC spleen cell cultures assayed by measuring plaque-forming cells on day 4. The data indicate that (a) whole spleen cells educated with SRBC exert potent antigen-specific suppression in the assay culture, (b) surface Ig- (sIg-) cells (T cells) prepared by either nylon-wool separation or fractionation on rabbit anti-mouse-Ig-coated polystyrene Petri dishes failed to generate suppressive activity when educated alone, in 2-mercaptoethanol, or in the presence of additional macrophages, (c) surface Ig (sIg+) (B) cells educated alone also failed to generate suppressor cells, and (d) mixing sIg- (T) and sIg+, Lyt 123- (B) cells reconstituted the ability to induce suppressor cells under these conditions. The antigen-primed cell actually required to transfer suppression was also characterized by separating cells using anti-Ig coated dishes, by fluorescence-activated cell sorting and by anti-Lyt treatment. All these methods clearly identified sIg+ (B) and not sIg+ (T) cells as the important educated cells. It is concluded that under our conditions, T cell-dependent B cells triggered by antigen during primary in vitro cultures cause potent specific feedback suppression of humoral responses. Possible mechanisms for this suppression, including antigen blockade or anti-idiotypic responses, are discussed.
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D002450:Cell Communication; D002478:Cells, Cultured; D004912:Erythrocytes / Q000276:immunology; D005246:Feedback; D005260:Female; D007519:Isoantigens / Q000032:analysis; D008211:Lymphocyte Cooperation; D008297:Male; D051379:Mice; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000954:Antigens, Surface; D007519:Isoantigens; D011947:Receptors, Antigen, B-Cell