Induction of antigen-specific immune tolerance by TGF-β-induced CD4+Foxp3+ regulatory T cells

Like natural CD4⁺CD25⁺ Treg cells, TGF-β-induced Treg cells also prevent allograft rejection in MHCmismatched organ transplantation models. In analyzing this effect with greater detail, we determined that injection of TGF-β-induced, alloactivated CD4 ⁺CD25⁺ cells induces antigen-specific immune tolerance in vivo. Increased CD4⁺CD25⁺ cells in recipients contribute to this immune tolerance. In addition, adoptive transfer of TGF-β-induced CD4⁺CD25⁺ cells did not result in significant toxic and side effects in recipients. These results indicate that TGF-β-induced, alloactivated CD4⁺CD25⁺ cells may provide a safe and effective approach to protect MHC-mismatched organ grafts from rejection in a clinical setting.