title: Cytolytic T cells activated by H-2-controlled E molecules cross-react with A molecules.
abstract: Cell-mediated lymphocytotoxicity was generated in four strain combinations differing only by the cell-surface expression of the class II E molecule controlled by the H-2 complex. The four combinations were: B10.D2(R107) anti-B10.A(3R), B10.A(4R) anti-B10.A(2R), B10.GD anti-B10.D2(R101), and B10.S(7R) anti-B10.S(9R). In all four of these combinations, the stimulator expresses E molecules on the cell surface, while the responder does not. The cytolytic T lymphocytes generated in the B10.D2(R107) anti-B10.A(3R) and B10.A(4R) anti-B10.A(2R) combinations reacted not only with the stimulator but also with strains that do not express cell-surface E molecules, in particular, strains carrying the H-2f and H-2q haplotypes. The cross-reactivity with E-negative strains could be blocked by monoclonal antibodies specific for the Af or Aq molecules but not by antibodies recognizing determinants on E or class I (K) molecules. The anti-H-2f cross-reactivity could be inhibited by H-2q cold targets and, reciprocally, the anti-H-2q reactivity could be blocked by H-2f cold targets. These findings are interpreted as indicating that the cytolytic T lymphocytes stimulated by E molecules can recognize and lyse cells lacking E molecules but expressing A molecules. The observed E-A cross-reactivity supports the notion of structural and functional relatedness between the A and E molecules and suggests a common evolutionary origin of the A- and E-encoding loci.
mesh_terms: D000818:Animals; D003429:Cross Reactions; D003602:Cytotoxicity, Immunologic; D005260:Female; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology*; D006649:Histocompatibility Antigens / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006183:H-2 Antigens; D006649:Histocompatibility Antigens; D000949:Histocompatibility Antigens Class II; C024138:I-E-antigen