Electronic Poster | Session 2

018 – Analysing recombinant anti-MOG antibodies associated with central nervous system demyelinating disorders

Alicia Zou (1) – Philomena Colagiuri (1) – Fiona Tea (1) – Deepti Pilli (1) – Joseph Angelo Lopez (1) – Vera Merheb (2) – Fiona Lee (2) – Russell Dale (1) – Fabienne Brilot (1)
Brain Autoimmunity Group, Kids Neuroscience Centre, Kids Research, The Children’s Hospital at Westmead, Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, Australia (1) – Brain Autoimmunity Group, Kids Neuroscience Centre, Kids Research, The Children’s Hospital at Westmead, Sydney, Australia (2)

Myelin oligodendrocyte glycoprotein (MOG) is a transmembrane protein of the myelin sheath that has been identified as an autoantibody target in a subset of central nervous system demyelinating disorders. The contribution of anti-MOG antibodies to human demyelination remains largely unclarified, as the use of polyclonal patient sera inhibits the characterisation of disease-relevant antibodies. To overcome these challenges, monoclonal recombinant antibodies (rAbs) have been generated from anti-MOG antibody-positive patients as well as healthy controls. rAbs were cloned from single IgG+ memory B cells sorted from PBMCs by flow cytometry. Heavy and light chain variable regions were amplified by RT-PCR, subcloned into IgG1 expression vectors, and co-transfected into HEK293T cells to produce productive rAbs. Based on B cell population analysis, the frequencies of IgG+ and IgA+ memory B cells were significantly elevated in patients compared to controls (p=0.05). 3/23 (13%) patient-derived rAbs and 0/15 (0%) control rAbs recognised human MOG in a flow cytometry live cell-based assay. One MOG-positive rAb (Kd 79.22 ng/ml) had comparable values to high affinity antibody ch8-18C5 (Kd 46.02 ng/ml), while another (Kd 3510.00 ng/ml) exhibited much weaker binding to MOG. There were no significant differences between the CDR3 mutation frequency of rAbs cloned from controls, MOG-negative patient rAbs, and MOG-positive patient rAbs. Further experiments aim to characterise the epitopes recognised by MOG-reactive rAbs and their ability to induce pathogenesis in vitro.