title: I-region-coded products expressed on both macrophages and thymus epithelium influence T-cell activities.
abstract: I-region-coded products expressed on the surface of both macrophages (Mph) and thymus epithelium were shown to restrict T-cell activities at the level of antigen recognition and determination of the T-cell repertoire. Thus keyhole limpet haemocyanin (KLH) -pulsed Mph could elicit a delayed-type hypersensitivity response in a KLH-sensitized mouse only when the Mph and the sensitized mouse were compatible at the I-A region of the major histocompatibility complex. Also, experiments with thymus-grafted chimaeras showed that I-region compatibility between the thymus of the cell donor and the reticuloendothelial system of the recipient was essential for successful transfer of the DTH reaction. Thus, F1 T cells derived from stem cells differentiating in a P1 thymus graft, where F1 parents (P1 and P2) differed only at defined regions of the H-2 complex, could always transfer sensitivity to P1 mice. However, successful transfer to P2 mice was possible only if P1 and P2 were H-21-compatible.
mesh_terms: D000818:Animals; D004848:Epithelium / Q000276:immunology; D000939:Epitopes; D005260:Female; D005802:Genes, MHC Class II; D005838:Genotype; D006238:Haploidy; D006968:Hypersensitivity, Delayed; D007114:Immunization; D008213:Lymphocyte Activation; D008264:Macrophages / Q000276:immunology*; D008285:Major Histocompatibility Complex; D051379:Mice; D008815:Mice, Inbred Strains; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology* / Q000637:transplantation; D014184:Transplantation, Homologous
chemical_list: D000939:Epitopes