title: HLA-DR4 (DRB1*0401) transgenic mice expressing an altered CD4-binding site: specificity and magnitude of DR4-restricted T cell response.
abstract: Optimum function of HLA-DR molecules in transgenic mice requires efficient interaction between the class II molecules on APCs and CD4 on T cells. Residues 110 and 139 of the second domain of class II molecules are considered to be critical for recognition of CD4. We generated an HLA-DR4beta(NT) transgene construct in which positions 110 and 139 were altered to resemble endogenous mouse H2 Abeta molecules. This construct was introduced into (B10 x SWR) embryos, and DR4beta(NT) transgenic mice were produced. The transgene was transferred into B10.RFB3 (Ebeta0 EalphaP) mice. The transgene-encoded DR4beta molecules paired with endogenous Ealpha chains to form stable DR4beta/Ealpha dimers expressed on the cell surface. The hybrid dimers showed similar Ag-binding specificity to HLA-DR4 molecules and positively selected CD4+ T cells in vivo. Immunization of HLA-DR4beta(NT) transgenic mice with DR4-restricted peptides induced T cell proliferation in vitro. While the purified T cells from DR4beta(NT) transgenic mice responded strongly to the HA(307-319) presented by M12C3 transfectants expressing altered DR4beta/Ealpha heterodimers, the response to the same peptides presented by transfectants expressing wild-type DR4beta/Ealpha molecules was substantially reduced. Taken together, these data confirmed in vitro studies on the importance of these residues in CD4-MHC class II interaction. The altered HLA-DR4beta transgenic mice were able to overcome the species barrier and generate efficient HLA-DR4-restricted CD4-specific immune responses. Thus, residues 110 and 139 were critical for the interaction of class II with CD4 T cells during thymic selection as well as peripheral immune responses.
authors.affiliation: Department of Immunology, Mayo Clinic and Medical School, Rochester, MN 55905, USA.
authors.forename: S
authors.initials: S
authors.lastname: Pan
authors.forename: T
authors.initials: T
authors.lastname: Trejo
authors.forename: J
authors.initials: J
authors.lastname: Hansen
authors.forename: M
authors.initials: M
authors.lastname: Smart
authors.forename: C S
authors.initials: CS
authors.lastname: David
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics / Q000276:immunology; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D015704:CD4 Antigens / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D003433:Crosses, Genetic; D006684:HLA-DR Antigens / Q000235:genetics* / Q000378:metabolism; D015804:HLA-DR4 Antigen / Q000235:genetics* / Q000378:metabolism; D059811:HLA-DRB1 Chains; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology; D019076:Transgenes / Q000276:immunology
chemical_list: D015704:CD4 Antigens; D006684:HLA-DR Antigens; D015804:HLA-DR4 Antigen; D059811:HLA-DRB1 Chains; C553505:HLA-DRB1*04:01 antigen; D011993:Recombinant Fusion Proteins