title: Non-toxic endotoxin polysaccharide induces soluble mediators which potentiate antibody production by murine retrovirus-suppressed splenocytes.
abstract: Mice infected with Friend leukemia virus show marked acquired immunodeficiency characterized by the impairment of immune function of spleen cells to various antigens, both in vivo and in vitro. The large mol. wt. endotoxin derived from Serratia marcescens, as well as a smaller non-toxic polysaccharide derivative, were found to augment the antibody responsiveness of spleen cells from normal as well as FLV-infected mice. In addition, serum from normal donor mice pretreated with BCG and injected either with endotoxin or the polysaccharide derivative potentiated the antibody response of spleen cells from both normal and FLV-infected mice. Similar enhancement was induced by "antibody response helper factor(s)" present in 3-5 day spleen culture supernatants from endotoxin or polysaccharide-treated spleen cells from normal mice. Enhancement of the antibody response of spleen cells from FLV-infected mice by the antibody helper activity was due to stimulation of B-lymphocytes and reversal of a defect in antibody helper factor(s) formation by macrophages. Similar antibody response enhancing activity was induced by both endotoxin and the non-toxic polysaccharide derivative in cultures of normal spleen cells, adherent spleen cell populations, peritoneal cells and the P388D1 macrophage cell line.
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D004731:Endotoxins / Q000494:pharmacology*; D005622:Friend murine leukemia virus; D007114:Immunization; D007942:Leukemia, Experimental / Q000276:immunology*; D008070:Lipopolysaccharides / Q000302:isolation & purification; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D012706:Serratia marcescens; D013154:Spleen / Q000276:immunology / Q000382:microbiology
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial