title: New TCR transgenic model for tracking allospecific CD4 T-cell activation and tolerance in vivo.
abstract: We have developed an adoptive transfer model system to visualize the dynamics of alloantigen-specific CD4+ T-cell activation in vivo. Using TCR-transgenic (tg) mice reactive to I-Ab(m12), we studied the clonal expansion and differentiation of alloreactive T cells by tracking the fate of adoptively transferred TCR-tg CD4+ T cells in syngeneic mice transplanted with skin grafts expressing I-Ab(m12). Following transplantation, alloantigen-specific TCR-tg CD4+ T-cell expansion was observed initially in the draining lymph nodes followed by the spleen. TCR-tg CD4+ T cells up-regulated CD69 and CD25 expression, developed an effector/memory surface phenotype and produced IFN-gamma in response to alloantigen ex vivo. Furthermore, we validate the model system as a means for studying the effects of tolerogenic regimens on alloreactive CD4+ T cells, demonstrating that CTLA4Ig inhibits alloantigen-dependent clonal expansion and effector function of TCR-tg CD4+ T cells in vivo. We describe the first model for tracking alloreactive CD4+ T-cell activation in vivo. It provides a powerful tool for studying CD4+ T-cell mediated alloimmune responses and mechanisms of tolerance induction in vivo.
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D016207:Cytokines / Q000096:biosynthesis / Q000378:metabolism; D005434:Flow Cytometry; D007150:Immunohistochemistry; D007519:Isoantigens / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016038:Skin Transplantation / Q000379:methods*; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D016207:Cytokines; D007519:Isoantigens; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins