title: Cell surface appearance of unexpected host MHC determinants on thymocytes from radiation bone marrow chimeras.
abstract: The phenotypic appearance of cell surface antigens on murine thymocytes from long-term radiation bone marrow chimeras was analyzed using indirect immunofluorescence and flow microfluorometry. Cells maturing in the thymi of these mice were typed for MHC (Kk, I-Ak, H-2b, Kb, and Ib) and non-MHC (Lyt 1, Ly 9, and TL) determinants. All cells were of donor origin as determined by non-MHC (Ly) phenotype in P1 leads to P2, P1 X P2 leads to P1, and P1 leads to P2 radiation chimeras. In contrast, the MHC phenotypes of these thymocytes were markedly affected by the host environment. Specifically, H-2 and I-A determinants of both parental phenotypes were detected on thymocytes from P1 leads to P1 X P2 chimeras; I-A determinants of host phenotype were present, whereas I-A determinants of donor phenotype were reduced on thymocytes from P1 X P2 leads to P1 chimeras; and thymocytes from P1 leads to P2 chimeras possessed H-2 and I-A determinants of host phenotype but showed reduction of donor I-A phenotype determinants. The appearance of host cell surface H-2 and I-A determinants on thymocytes from chimeras closely parallels the functional recognition of MHC determinants by T cells from chimeric mice and thus may be significantly related to the development of the self-recognition repertoire by maturing T cells.
mesh_terms: D000818:Animals; D000954:Antigens, Surface; D001853:Bone Marrow / Q000276:immunology; D003433:Crosses, Genetic; D000939:Epitopes; D005455:Fluorescent Antibody Technique; D008285:Major Histocompatibility Complex; D051379:Mice; D008805:Mice, Inbred A; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D011828:Radiation Chimera; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000954:Antigens, Surface; D000939:Epitopes