B cell-targeted CAR-T treatment of CNS Autoimmunity

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PROJECT SUMMARY An immense need for selective and antigen-specific immunotherapy without global immunosuppression exists for autoimmune diseases such as multiple sclerosis (MS). This has prompted exploration of chimeric antigen receptor (CAR) T cell utilization to specifically eliminate autoreactive cells. The contribution of B cells to MS and related diseases is recognized in part by the success of B cell depletion therapies. However, depletion of B cells for neuroimmunologic diseases are not selective enough to avoid safety concerns related to non-specific B cell depletion, including immunosuppression and infection. Hence, we seek to develop CAR T cells to target antigen-specific, autoreactive B cells using a B cell-dependent version of experimental autoimmune encephalomyelitis (EAE), an animal model with relevance to inflammatory demyelinating diseases of the central nervous system (CNS) such as MS. In preliminary studies, we have created a unique version of CAR T cells in which peptide MHCII (pMHCII) is fused with signaling domains in order to recognize specific T cell receptors (TCRs). We demonstrate that these pMHCII-CAR T cells specifically recognize a cognate TCR in vitro and in vivo and are capable of limiting EAE severity. We now seek to develop antigen-specific B cell depletion for the treatment of B cell-dependent EAE in two aims. In Aim 1, we will optimize survival of, and killing by, myelin oligodendrocyte glycoprotein (MOG)-expressing CAR T cells targeting MOG-specific B cells in both prevention and treatment of EAE. In Aim 2, we will utilize pMHCII-CAR T cells targeting MOG-specific TCRs in combination with MOG-CAR T cells targeting auto-reactive B cells in EAE. In sum, our proposed studies will explore the potential of a CAR T cell approach for the treatment of CNS autoimmunity by addressing how to optimally eliminate TCR and BCR specificities without leading to blanketed immunosuppression.