title: Characterization of autoreactive T cells. Relative importance of self-peptides versus MHC.
abstract: The degree to which processed self-peptides contribute to the stimulation of autoreactive T cells has not been determined. In this study we have analyzed a panel of autoreactive T cell hybridomas from normal C57BL/26 mice produced by fusing peripheral lymph node cells with a variant of the BW5147 thymoma line, which does not express endogenous TCR alpha- and beta-chains. All of the autoreactive hybridomas responded to spleen cells expressing the syngeneic I-Ab allele, but not to allogeneic spleen cells. Although all hybridomas were I-Ab restricted, they demonstrated different patterns of reactivity to a panel of APC expressing I-Ab but derived from different genetic backgrounds. In a panel of APC expressing recombinant I-A molecules, changes in the second half of the first domain, which encodes alpha-helix segments that flank the Ag binding site and directly contact the TCR V regions in proposed models, eliminated reactivity of all hybridomas tested. In addition, most of the autoreactive hybridomas also demonstrated inhibition of reactivity to mutations in the amino half of the first domain of the I-A alpha- and beta-chains, which encodes the beta-pleated sheet of the floor of the Ag-binding groove. To confirm the role of processed peptides in the different patterns of reactivity, APC were incubated with competitor Ag and fixed by glutaraldehyde cross-linking before incubation with the autoreactive T hybridomas. The hybridomas were effectively inhibited by exogenous protein and peptide Ag. These results indicate that processed self-peptides are required to activate the autoreactive T cells.
authors.affiliation: Laboratory of Immunogenetics and Transplantation, Brigham and Women's Hospital, Boston, MA.
authors.forename: Y S
authors.initials: YS
authors.lastname: Wang
authors.forename: D L
authors.initials: DL
authors.lastname: Perkins
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000276:immunology*; D015551:Autoimmunity; D001667:Binding, Competitive; D003001:Cloning, Molecular; D004306:Dose-Response Relationship, Immunologic; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006825:Hybridomas / Q000276:immunology*; D007156:Immunologic Memory; D007376:Interleukin-2 / Q000378:metabolism; D008285:Major Histocompatibility Complex / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009113:Muramidase / Q000494:pharmacology; D010047:Ovalbumin / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D001324:Autoantigens; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D010047:Ovalbumin; D009113:Muramidase