MOGAD patient autoantibodies induce complement, phagocytosis, and cellular cytotoxicity
Soumya S. Yandamuri, Beata Filipek, Abeer H. Obaid, Nikhil Lele, Joshua M. Thurman, Naila Makhani, Richard J. Nowak, Yong Guo, Claudia F. Lucchinetti, Eoin P. Flanagan, Erin E. Longbrake, Kevin C. O’Connor
Soumya S. Yandamuri, Beata Filipek, Abeer H. Obaid, Nikhil Lele, Joshua M. Thurman, Naila Makhani, Richard J. Nowak, Yong Guo, Claudia F. Lucchinetti, Eoin P. Flanagan, Erin E. Longbrake, Kevin C. O’Connor
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Research Article Neuroscience

MOGAD patient autoantibodies induce complement, phagocytosis, and cellular cytotoxicity

Abstract

Myelin oligodendrocyte glycoprotein (MOG) antibody–associated disease (MOGAD) is an inflammatory demyelinating CNS condition characterized by the presence of MOG autoantibodies. We sought to investigate whether human MOG autoantibodies are capable of mediating damage to MOG-expressing cells through multiple mechanisms. We developed high-throughput assays to measure complement activity (CA), complement-dependent cytotoxicity (CDC), antibody-dependent cellular phagocytosis (ADCP), and antibody-dependent cellular cytotoxicity (ADCC) of live MOG-expressing cells. MOGAD patient sera effectively mediate all of these effector functions. Our collective analyses reveal that (a) cytotoxicity is not incumbent on MOG autoantibody quantity alone; (b) engagement of effector functions by MOGAD patient serum is bimodal, with some sera exhibiting cytotoxic capacity while others did not; (c) the magnitude of CDC and ADCP is elevated closer to relapse, while MOG-IgG binding is not; and (d) all IgG subclasses can damage MOG-expressing cells. Histopathology from a representative MOGAD case revealed congruence between lesion histology and serum CDC and ADCP, and we identified NK cells, mediators of ADCC, in the cerebrospinal fluid of relapsing patients with MOGAD. Thus, MOGAD-derived autoantibodies are cytotoxic to MOG-expressing cells through multiple mechanisms, and assays quantifying CDC and ADCP may prove to be effective tools for predicting risk of future relapses.

Authors

Soumya S. Yandamuri, Beata Filipek, Abeer H. Obaid, Nikhil Lele, Joshua M. Thurman, Naila Makhani, Richard J. Nowak, Yong Guo, Claudia F. Lucchinetti, Eoin P. Flanagan, Erin E. Longbrake, Kevin C. O’Connor

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Figure 1

MOG IgG1 mAb induces CDC and ADCP of live MOG-expressing cells in vitro.

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MOG IgG1 mAb induces CDC and ADCP of live MOG-expressing cells in vitro....
(A) Schematic of CDC and ADCP assays utilizing live HEK cells partially transfected with full-length human MOG-GFP, incubated with 1 μg/mL MOG or control AChR mAbs, followed by the addition of NHS for CDC or macrophages for ADCP induction. MAC formation and cell death for CDC and phagocytosis and loss of MOG+ cells for ADCP were quantified by flow cytometry. (B and C) Contour plots depict (B) MAC formation and (C) death of HEK cells based on MOG expression upon incubation with MOG versus AChR mAbs in the CDC assay. (D and E) Macrophage phagocytosis of MOG+ cells is shown by (D) dot plots depicting the frequency of GFP+ macrophages, and (E) histograms of MOG+ cells out of the total HEK cell population, upon incubation with MOG versus AChR mAbs in the ADCP assay. (F and G) Histograms show (F) MAC formation and (G) death of MOG– versus MOG+ HEK cells upon incubation with MOG versus AChR mAbs in the CDC assay. All graphs are representative. Each experiment was performed at least 3 times in duplicate. Frequencies of indicated gates depicted on plots.