title: An MHC class Ib-restricted TCR that cross-reacts with an MHC class Ia molecule.
abstract: TCR transgenic 6C5 T cells recognize an insulin B chain epitope presented by the nonclassical class I MHC molecule, Qa-1(b). Positive selection of these T cells was shown previously to require Qa-1(b). Despite dedicated specificity for Qa-1(b), evidence presented in the current study indicates that 6C5 T cells can cross-recognize a classical class I molecule. Clonal deletion was observed unexpectedly in 6C5.H-2(bxq) mice, which do not express I-E MHC class II molecules and thus should not be subject to superantigen-mediated negative selection. 6C5 T cells were observed to respond in vivo and in vitro to spleen cells from allogeneic H-2(q) mice, and specificity was mapped to D(q). Evidence was obtained for direct recognition of D(q), rather than indirect presentation of a D(q)-derived peptide presented by Qa-1(b). Polyclonal CD8(+) T cells from class Ia-deficient K(b)D(b-/-) mice reacted in vitro to allogeneic spleen cells with an apparent frequency comparable to conventional class Ia-restricted T cells. Our results provide a clear example of a Qa-1-specific TCR that can cross-react with a class Ia molecule and evidence supporting the idea that this may be a common property of T cells selected by class Ib molecules.
authors.affiliation: Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Reed-Loisel
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Sullivan
authors.forename: Oskar
authors.initials: O
authors.lastname: Laur
authors.forename: Peter E
authors.initials: PE
authors.lastname: Jensen
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D019070:Cell Lineage / Q000235:genetics / Q000276:immunology; D017637:Clonal Deletion; D003433:Crosses, Genetic; D006183:H-2 Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism*; D018089:Superantigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D006183:H-2 Antigens; D015395:Histocompatibility Antigens Class I; C032907:Q surface antigens; D011948:Receptors, Antigen, T-Cell; D018089:Superantigens