title: Modulation of immune response by bacterial lipopolysaccharide (LPS): cellular basis of stimulatory and inhibitory effects of LPS on the in vitro IgM antibody response to a T-dependent antigen.
abstract: The role of thymus-derived lymphocytes (T cells) in LPS modulation of T cell-dependent antibody responses has been investigated. We have assessed the effect of LPS on the primary anti-TNP response to TNP-SRBC of cultures of whole spleen cells or T cell-depleted spleen cells that were supplemented with various subpopulations of carrier-primed (SRBC) spleen cells. The TNP-PFC response was enhanced in the presence of irradiated SRBC-primed spleen cells by addition of 0.16 to 20 microgram/ml LPS, but inhibition was observed when irradiation of primed cells was omitted. Enhancement but no inhibition occurred when added primed cells were first passed through a nylon wool column. LPS-mediated enhancement was dependent on a T cell in the primed population. These results suggest that LPS modulation of antibody synthesis is dependent on two populations of antigen-specific cells that have opposing effects on B cell responses to a T-dependent antigen: a helper cell that is irradiation resistant, nonadherent to nylon wool, and sensitive to anti-T cell serum, and a suppressor cell that is irradiation sensitive and adherent to nylon wool.
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D004307:Dose-Response Relationship, Radiation; D007111:Immunity, Cellular; D007075:Immunoglobulin M / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology* / Q000528:radiation effects
chemical_list: D002352:Carrier Proteins; D007075:Immunoglobulin M; D008070:Lipopolysaccharides