title: T-cell recognition of a chimaeric class II/class I MHC molecule and the role of L3T4.
abstract: In addition to expressing clonally distributed antigen-specific and major histocompatibility complex (MHC)-restricted receptors, T cells also express non-clonally distributed surface molecules that are involved in T-cell function. Among the most intriguing of the latter are L3T4 and Lyt 2, which are expressed on individual T lymphocytes in striking, though not absolute, concordance with their restriction by either class II or class I MHC determinants, and which are thought to contribute to the overall avidity of T-cell interactions by binding to monomorphic determinants on class II and class I MHC molecules, respectively. To examine the ability of T cells to recognize a single class II domain in the absence of the remainder of the Ia molecule, as well as to evaluate the structural basis for the putative interaction of L3T4 with Ia, a recombinant class II/class I murine MHC gene was constructed and introduced into mouse L cells. Here we demonstrate that a subset of class II allospecific cytotoxic T lymphocytes (CTL) can specifically recognize and lyse L-cell transfectants expressing an isolated polymorphic A beta 1 domain, and that anti-L3T4 antibody can block such killing, a result inconsistent with the highly conserved membrane-proximal domains of Ia acting as unique target sites for L3T4 binding.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology*; D002450:Cell Communication; D002678:Chimera; D005455:Fluorescent Antibody Technique; D005802:Genes, MHC Class II; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics; D008285:Major Histocompatibility Complex; D051379:Mice; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000950:Antigens, Ly; D000954:Antigens, Surface; D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II