W200 - High-Throughput Identification and Characterization of Patient-Derived Monoclonal Autoantibodies in Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease (MOGAD)

Abstract Text: Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is a CNS demyelinating autoimmune disorder characterized by autoantibodies targeting MOG. However, the mechanisms by which these autoantibodies mediate disease pathology remain unclear, limiting treatment options for patients. To address this knowledge gap, we aim to understand the immunopathology of autoantibody-mediated MOGAD by producing and studying patient-derived monoclonal antibodies (mAbs), and characterizing their somatic mutational load, clonal expansion, isotype, and binding strength—indicators of antigen-driven maturation and potential Fc-mediated pathology. However, understanding the heterogeneity of autoantibody responses across MOGAD patients necessitates generating a large library of mAbs, and consequently a high-throughput approach. Accordingly, we implemented an optofluidic-based antigen-specific method on the Beacon platform to identify and isolate patient-derived MOG-specific B cells, from which B-cell receptor (BCR) sequences were used to generate mAbs. We identified B cells from three patients producing MOG-binding IgG antibodies and found 16 unique pairs of BCR heavy and light chain sequences. Using this data, we generated mAbs and tested their binding specificity using a live MOG-expressing cell-based assay (CBA) and MOG-based ELISA. One mAb, with high mutational frequency, tested positive on the ELISA. Additional mAbs are being tested by CBAs for binding and Fc-mediated effector functions. Herein, we present a high-throughput strategy that has the potential to expedite antibody discovery workflows for rare pathogenic cell types, advancing our mechanistic understanding of MOGAD and enabling patient-specific therapeutic strategies and improved clinical outcomes.