title: Origin of a T cell clone with a mismatched combination of MHC restriction and coreceptor expression.
abstract: Although the existence of a large number of CD8+ class II MHC-specific CTLs had long been noticed, the origin of such T cells with a discordant combination of specificity and phenotype has been a mystery in the positive selection model. Recent reports suggesting the independency of the positive selection of T cells from coreceptor-mediated signals raised a possibility that they might be the progeny of putative transitional, mismatched, single-positive cells appearing before positive selection as proposed in the stochastic/selective model. By developing transgenic mice carrying TCR alpha and beta chain genes of a CD8+ class II MHC Ag-specific allogeneic CTL clone QM11, the origin of such T cells with mismatched TCR specificity and coreceptor expression was studied. The results indicate that QM11 belongs to a conventional CD8+ T cell population whose maturation is dependent on a class I (or class I-like) MHC product. Consequently, the reactivity of QM11 to I-Ak can be considered to be an accidental cross-reaction.
authors.affiliation: Laboratory of Cellular Immunology, Mitsubishi Kasei Institute of Life Sciences, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Eshima
authors.forename: Y
authors.initials: Y
authors.lastname: Takagaki
authors.forename: S
authors.initials: S
authors.lastname: Hanaoka
authors.forename: M
authors.initials: M
authors.lastname: Katsuki
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: S
authors.initials: S
authors.lastname: Yamazaki
authors.forename: N
authors.initials: N
authors.lastname: Shinohara
mesh_terms: D000818:Animals; D001483:Base Sequence; D016827:CD8 Antigens / Q000096:biosynthesis* / Q000235:genetics; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002999:Clone Cells; D003601:Cytotoxicity Tests, Immunologic; D000939:Epitopes / Q000096:biosynthesis; D005434:Flow Cytometry; D006183:H-2 Antigens / Q000235:genetics; D000949:Histocompatibility Antigens Class II / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*
chemical_list: D016827:CD8 Antigens; D000939:Epitopes; D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D016693:Receptors, Antigen, T-Cell, alpha-beta