Treatment of experimental autoimmune encephalomyelitis with engineered bi-specific Foxp3+ regulatory CD4+ T cells.

The use of autoantigen-specific regulatory T cells (Tregs) as a cellular therapy for autoimmune diseases is appealing. However, it is challenging to isolate and expand large quantity of Tregs expressing disease-relevant T-cell receptors (TCR). To overcome this problem, we used an approach aiming at redirecting the specificity of polyclonal Tregs through autoreactive TCR gene transfer technology. In this study, we examined whether Tregs engineered through retroviral transduction to express a TCR cross-reactive to two CNS autoantigens, myelin oligodendrocyte glycoprotein (MOG) and neurofilament-medium (NF-M), had a superior protective efficacy compared with Tregs expressing a MOG mono-specific TCR. We observed that engineered Tregs (engTregs) exhibited in vitro regulatory effects related to the antigenic specificity of the introduced TCR, and commensurate in potency with the avidity of the transduced TCR. In experimental autoimmune encephalomyelitis (EAE), adoptively transferred engTregs proliferated, and migrated to the CNS, while retaining FoxP3 expression. EngTregs expressing MOG/NF-M cross-reactive TCR had superior protective properties over engTregs expressing MOG-specific TCR in MOG-induced EAE. Remarkably, MOG/NF-M bi-specific TCR-engTregs also improved recovery from EAE induced by an unrelated CNS autoantigen, proteolipid protein (PLP). This study underlines the benefit of using TCRs cross-reacting towards multiple autoantigens, compared with mono-reactive TCR, for the generation of engTregs affording protection from autoimmune disease in adoptive cell therapy.