title: CD8+ T cells specific to the exogenous antigen. Mode of antigen recognition and possible implication in immunosuppression.
abstract: This study demonstrates and characterizes CD8+ T cells specific to the exogenous Ag, bovine alpha s1-casein. Purified CD8+ T cells from alpha s1-casein-primed lymph node cells proliferated well in response to an alpha s1-casein derivative, trypsin-digested alpha s1-casein. CD8+ T cell repertoire for the exogenous Ag was directly demonstrated in the primary culture condition. The intact alpha s1-casein primed the responding CD8+ T cells in vivo more efficiently than the tryptic alpha s1-casein; however, the in vitro proliferative response by the intact alpha s1-casein was weaker than that of the tryptic alpha s1-casein. CD8+ T cells recognized the exogenous Ag in association with MHC class I molecules as revealed by an Ab-blocking study. The major immunodominant region for the CD8+ T cells was mapped to region 136-151 of alpha s1-casein, and peptide 136-151 primed the responding CD8+ T cells but not any CD4+ T cells. Peptide 136-151 is the CD8+ T cell-specific determinant. Upon antigenic stimulation, the exogenous Ag-specific CD8+ T cells produced a significant level of IFN-gamma, which has immune suppressive activity for IgE synthesis. Our study strongly implies that CD8+ T cells that proliferate and produce IFN-gamma in response to the exogenous Ag would play a vital role in Ag-specific immunosuppression.
authors.affiliation: Department of Applied Biological Chemistry, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hisatsune
authors.forename: K
authors.initials: K
authors.lastname: Nishijima
authors.forename: M
authors.initials: M
authors.lastname: Kohyama
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: S
authors.initials: S
authors.lastname: Kaminogawa
mesh_terms: D000367:Age Factors; D000818:Animals; D000941:Antigens / Q000276:immunology*; D002364:Caseins / Q000276:immunology* / Q000378:metabolism; D002417:Cattle; D002999:Clone Cells / Q000276:immunology; D007108:Immune Tolerance; D016056:Immunodominant Epitopes / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D008198:Lymph Nodes / Q000276:immunology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014357:Trypsin / Q000378:metabolism
chemical_list: D000941:Antigens; D002364:Caseins; D016056:Immunodominant Epitopes; D008222:Lymphokines; D007371:Interferon-gamma; D014357:Trypsin