CD20+inflammatory T-cells are present in blood and brain of multiple sclerosis patients and can be selectively targeted for apoptotic elimination.

ABSTRACT

BACKGROUND: A subset of T-cells expresses the B-cell marker CD20 and in rheumatoid arthritis secretes Interleukin (IL)-17. IL-17 secreting T-cells (Th17) have also been implicated in the inflammatory response in the central nervous system in multiple sclerosis (MS) and may be a potential target for elimination by biologic therapeutics. ScFvRitsFasL comprises of a rituximab-derived antibody fragment scFvRit genetically fused to human soluble FasL that specifically eliminated T-cells. OBJECTIVE: To determine the presence and phenotype of CD20+T-cells in blood and brain of MS patients. Second, to determine whether scFvRitsFasL can selectively eliminate CD20+T-cells. After CD20-selective binding, scFvRitsFasL is designed to trigger FasL-mediated activation-induced cell death of T-cells, but not B-cells. METHODS: Flow cytometry and immunohistochemistry were used to screen for CD20+inflammatory T-cells in MS blood and brain tissue. ScFvRitsFasL pro-apoptotic activity was evaluated by Annexin-V/PI staining followed by flow cytometry assessment. RESULTS: Peripheral blood (n=11) and chronic but not active lesions of MS patient brains (n=5) contained CD20+inflammatory T-cells. Activated CD20+T-cells were predominantly CD4+and secreted both IL-17 and INF-γ. ScFvRitsFasL triggered CD20-restricted FasL-mediated activation-induced cell death in peripheral blood CD20+T-cells, but not CD20+B-cells. CONCLUSION: CD20+inflammatory T-cells are present in blood and chronic brain lesions of MS patients. ScFvRitsFasL selectively eliminated CD20+T-cells and may eliminate pathogenic T-cells without B-cell depletion.