Developing non-immunosuppressive immune-based therapeutics for targeted treatment of autoimmune diseases

Project Summary Pemphigus vulgaris is a devastating B-cell mediated autoimmune disease. Autoantibodies produced by B cells targeting desmoglein-3 (Dsg3), a desmosomal protein, critical for intercellular adhesion, is responsible for the mucosal-dominant type of the disease and cause painful deep erosions in the mucosa. Anti-Dsg3 autoantibodies result in the disruption of the keratinocytes' connections, and, thereby, cause the formation of blisters and erosions. The direct pathogenic role of anti-Dsg3 autoantibodies in PV has been established. Monovalent antibodies have been shown to be sufficient to result in the formation of blisters. Standard treatments include immunosuppressive drugs that globally suppress the immune system. The goal of this project is to develop novel, targeted, immuno-therapeutic approaches to specifically and precisely target and deplete autoreactive B cells recognizing Dsg3. Established Dsg3 specific autoreactive B cells are used to optimize these methods. We will determine the efficacy and specificity of the approach using peripheral blood mononuclear cells (PBMCs) obtained from PV patients in different phases of the disease, including treatment- naive and relapse, and in vivo mouse models of the disease. Successful completion of this study will help translate the methods into a preclinical and, eventually, a clinical setting. The ease of production, low cost, compared to cell-based targeted approaches, and the lack of off-target side-effects compared to the existing treatments for PV make the proposed therapeutics breakthrough treatment options. Furthermore, the technology developed here can have wider applications to all autoantibody-driven diseases by directly targeting autoreactive cells without causing global immunosuppression.