Postdoctoral Associate Yale Univ. New Haven, Connecticut, United States
Disclosure(s):
Fatemeh Khani Habibabadi, PhD: No relevant disclosure to display
Introduction/Rationale: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune demyelinating disorder of the central nervous system classically characterized by optic neuritis, transverse myelitis, and/or encephalitis. Although MOG-specific autoantibodies are a diagnostic hallmark, the cellular mechanisms underlying their production remain poorly understood. In several autoimmune diseases, impaired B-cell tolerance checkpoints allow autoreactive B cells to escape negative selection and may contribute to the production of pathogenic antibodies. Here, we investigate whether similar tolerance defects contribute to MOGAD pathogenesis.
Methods: A well-established tolerance assay was utilized to assess checkpoint fidelity by generating recombinant monoclonal antibodies (mAbs) from naïve B-cell subsets downstream of the central and peripheral tolerance checkpoints. Peripheral B cells were enriched by negative selection, and single transitional/new emigrant (CD19⁺CD21ˡᵒCD10⁺IgMʰⁱCD27⁻) and mature naïve (CD19⁺CD21⁺CD10⁻IgM⁺CD27⁻) B cells were sorted by flow cytometry. Ig heavy and light chain genes were amplified, and mAbs were expressed and tested for polyreactivity by ELISAs against dsDNA, insulin, and LPS and for autoreactivity against HEp-2 cell lysates. Additionally, single-cell 5′ gene expression data paired with B-cell receptor (BCR) sequencing were analyzed using a droplet-based single-cell RNA sequencing platform to define naïve B-cell expression profiles together with their corresponding immunoglobulin heavy and light chain genes.
Results: Preliminary analyses suggest that tolerance checkpoint fidelity in MOGAD differs from that observed in other autoimmune diseases. Ongoing studies will expand these analyses in larger cohorts to better delineate the integrity of central and peripheral tolerance checkpoints and their contribution to MOGAD immunopathology.
