title: Induction of suppression by a murine nonspecific suppressor-inducer cell line (M1-A5).
abstract: A murine nonspecific suppressor-inducer cell line (M1-A5) was established by the limiting dilution method from the spleen cells of a mouse bearing an advanced methylcholanthrene-induced fibrosarcoma. Indirect immunofluorescence studies demonstrated that the M1-A5 cells were Thy-1-, sIg-, Ly-5+, MAC-, and 45% asialo GM1+. The M1-A5 cells were able to activate suppressor cells from unprimed, syngeneic normal spleen cells. These activated cells inhibited antibody production by cocultured syngeneic lymphoid cells. Induction of suppression by the M1-A5 cells was via the release of a suppressor-inducing factor, which was found to be protein in nature. Kinetic studies showed that when M1-A5 cells were separated from NSC by a dialysis tubing in Marbrook vessels, the M1-A5 cells required a minimum of 8 hr incubation period before suppressor cell activity could be demonstrated in precursor cells. On the other hand, induction of suppression by the suppressor-inducing factor required a minimum of 3 hr exposure of the precursor cells to the factor.
mesh_terms: D000818:Animals; D002460:Cell Line; D006462:Hemolytic Plaque Technique; D007108:Immune Tolerance; D007700:Kinetics; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D010641:Phenotype; D013491:Suppressor Factors, Immunologic / Q000096:biosynthesis / Q000502:physiology; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology* / Q000378:metabolism
chemical_list: D013491:Suppressor Factors, Immunologic