Human primary CD4+ T cells modified by lentiviral transduction to express human TCR 164 that recognizes a pancreatic beta cell-derived peptide in the context of HLA-DR4. The TCR-transduced cells can be transferred to NSG mice engineered to express HLA-DR4 and deficient for murine class II MHC molecules, allowing long-term survival (up to 3 months post-transfer) and avoidance of lethal graft-versus-host disease (GVHD).