title: Inactivation of specific anti-H-2 suppressor T cells by antisera to I-J and I-C subregion products of the H-2 complex.
abstract: Two antisera to Ia antigens, products of the H-2 complex I-Cd and I-JkEk subregions, respectively, have been obtained by immunization of the F1 hybrids of recombinant strains of mice. These antisera are shown to display a 50% cytotoxic effect in vitro, in the presence of complement, upon lymphocyte populations immune to the H-2-complex antigens and enriched for specific suppressor T cells (SSTC) by fractionation on a monolayer of target cells. The specificity of anti-Ia cytotoxins is shown by cross-antibody absorption with T and B cells of mice originating from the recombinant H-2 haplotypes and bearing either particular I-Cd, I-Jk and I-Ek antigens, or their combinations. Anti-I-Cd cytotoxins were found to react with both B and T cells, but at a different rate, and the anti-I-JkEk serum contains two antibody types directed to I-Ek and I-Jk products, respectively, the latter being able to react preferently with T cells. Although both antisera do inactivate the in vitro SSTC function in the presence of complement to a similar degree, the inactivating action of the anti-I-Cd serum, but not that of the anti-I-JkEk serum, occurs without complement. SSTC are shown to bear both Ia-antigens, I-J and I-C, as shown by both inactivation of the anti-suppressor effect of the antisera absorbed with spleen cells of different H-2 origin, and variation of the H-2 origin of SSTC pretreated with the intact antisera. It is suggested that these two markers, located on the same SSTC, function differently in SSTC immune to the H-2 antigens, and I-C antigen expression on the SSTC surface is presumed to be required for their interaction with the inhibited responder T cells proliferating in MLC.
mesh_terms: D000483:Alleles; D000818:Animals; D003602:Cytotoxicity, Immunologic; D004261:DNA Replication; D005802:Genes, MHC Class II; D006183:H-2 Antigens / Q000235:genetics*; D007106:Immune Sera; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex; D051379:Mice; D008815:Mice, Inbred Strains; D013045:Species Specificity; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D006183:H-2 Antigens; D007106:Immune Sera