title: Primary in vitro plaque-forming cell response to DAGG-Ficoll: LPS-induced enhancement mediated by interleukin-1.
abstract: The specific primary in vitro plaque-forming cell (PFC) response of C57B1/6 nu/nu spleen cells to the Type 2 T-independent (TI-2) antigen DAGG-Ficoll was analysed in the absence of T cell help in a serum-free medium. Lipopolysaccharide (LPS) enhancement of the antigen-specific response was shown to be mediated by soluble factors contained in the supernatants of LPS-induced bone marrow-derived macrophages. The activity of these supernatants was not associated with residual LPS, since the antigen-specific response of B cells from mice genetically deficient in LPS receptors was equally well enhanced. The activity of these supernatants was associated with interleukin-1 (IL-1) and partially purified IL-1 prepared from P388D1 cells also enhanced the primary in vitro response to DAGG-Ficoll. Limiting dilution analysis experiments showed that only in the presence of exogenously added IL-1 could a single cell type, presumably the B cells, be shown to be limiting.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D002478:Cells, Cultured; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D005362:Ficoll / Q000031:analogs & derivatives / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D007375:Interleukin-1 / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D011134:Polysaccharides / Q000276:immunology*; D013154:Spleen / Q000276:immunology
chemical_list: C026941:2,4-dinitrophenyl-alanylglycylglycyl-ficoll; D007375:Interleukin-1; D008070:Lipopolysaccharides; D011134:Polysaccharides; D005362:Ficoll