title: Alloantigens determined by a second D region locus elicit a strong in vitro cytotoxic response.
abstract: The newly defined L antigen (previously designated D') has been studied with the CML assay. Balb/c-H-2db mice, which carry a loss mutation in the D region, were found to generate anti-L cytotoxic effector cells when stimulated with wild-type (BALB/c) cells. When the target cells were treated with an antiserum against L, cytolysis by BALB/c-H-2db anti-BALB/c effectors was completely blocked. However, an antiserum against D, the antigen that bears the D region private specificity, had no effect on the anti-L cytotoxic response. In a control CML experiment that was specific for the D antigen, the antiserum to L had no effect, whereas the antiserum to D blocked completely. These results indicate that the L and D antigens are recognized in a CML response as separate entities on the cell surface. In an allogeneic response to the products of the D region, cytotoxic effectors were generated that were specific for L in addition to those specific for D. This conclusion was supported by blocking experiments with either antisera or unlabeled targets. These functional studies thus extend previous co-capping and immunochemical studies, and further support the hypothesis that L is a third transplantation antigen similar to the K and D antigens.
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D002874:Chromosome Mapping; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D000939:Epitopes; D007106:Immune Sera / Q000494:pharmacology; D007519:Isoantigens / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D013154:Spleen / Q000276:immunology
chemical_list: D000939:Epitopes; D007106:Immune Sera; D007519:Isoantigens