title: Characterization of an Lyt-2+ alloreactive cytotoxic T cell clone specific for H-2Db that cross-reacts with I-Ek.
abstract: An alloreactive cytotoxic T cell clone (433) possessing the L3T4-, Lyt-2+ phenotype is described that shows a double specificity. It has been derived from unprimed BALB/c (H-2d) spleen cells by repetitive in vitro restimulation with C57BL/6(H-2b) cells. The specificity of clone 433 was determined in cytotoxicity and proliferation experiments. One specificity was for the class I antigen H-2Db and the second was for the class II antigen I-Ek. Inhibition of cytotoxicity with monoclonal antibodies confirmed these results. Cold target competition experiments demonstrated that the two specificities were mediated by the same cell population. Anti-Lyt-2 antibodies inhibited only the H-2Db- but not the I-Ek-specific lysis, suggesting a higher affinity of the antigen receptor for I-Ek than for Db. To our knowledge, this is the first description of a T cell clone that is specific for a class I antigen and cross-reacts heteroclitically with a class II antigen.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000950:Antigens, Ly / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D002999:Clone Cells / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006183:H-2 Antigens / Q000276:immunology*; D006649:Histocompatibility Antigens / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D008285:Major Histocompatibility Complex; D051379:Mice; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D000954:Antigens, Surface; D006183:H-2 Antigens; D006649:Histocompatibility Antigens; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen