title: Suppression of a polyclonal B-cell response by supernatants from the murine autologous mixed lymphocyte reaction.
abstract: Previously, we have demonstrated that supernatants from autologous mixed lymphocyte (AMLR) cultures contain helper factors which can mediate the development of a cytotoxic T-cell response to hapten modified self. In the current study, the effect of AMLR supernatants on the humoral response was explored. BALB/C splenic non-T cells produced a large polyclonal antibody response to lipopolysaccharide (LPS), as measured in a Protein A SRBC plaque assay. Surprisingly, syngeneic AMLR supernatants suppressed the LPS-induced generation of plaque-forming cells. The presence of T cells in the stimulated cultures did not affect suppressor activity. The decreased response was not the result of a shift in kinetics, as maximal activity was observed on Day 4, whether or not AMLR supernatants were added. The AMLR culture supernatants were most effective in suppressing the plaque-forming cell response when added at the initiation of culture. AMLR supernatants added after 24 hr of culture resulted in only about 50% of maximum suppression. Supernatants added at 48 or 72 hr had no effect. Interferon-gamma (IFN-gamma) has been detected in AMLR culture supernatant and has been reported to suppress the development of plaque-forming cells in response to LPS. However, it is unlikely the suppressive activity observed in these studies is due to IFN-gamma. Dialysis of the AMLR culture supernatant against a pH 2 buffer for 24 hr or incubation at 70, 80, or 90 degrees C for 10 min, treatments that inactivate IFN-gamma, enhanced suppression. These results suggest that in addition to cytotoxic-T-cell helper factors, the cellular interactions in the AMLR induces the production of a stable mediator(s) which is able to directly suppress B cells at an early stage of their development into plasma cells.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D002474:Cell-Free System; D006462:Hemolytic Plaque Technique; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D013491:Suppressor Factors, Immunologic / Q000502:physiology*
chemical_list: D008070:Lipopolysaccharides; D013491:Suppressor Factors, Immunologic