Recombinant antibodies binding to cytoskeletal structural proteins in post Covid-19 vaccination demyelination syndromes
Amol Raisingani1, Jiayuan Liu1, Jerry Lin1, Qijiang Yan1, Saud Sadiq1
1Tisch Multiple Sclerosis Research Center of New York
Objective:
To investigate the pathogenesis of demyelination in  patients receiving vaccination for SARS-COV-2. 
Background:
Vaccines against SARS-COV-2 elicit an antibody response and reduce severity of infection, but rarely are associated with adverse neurological events. We report on two such patients who developed post-vaccinal demyelinating syndromes. 
Design/Methods:
CSF samples from these two patients were tested for SARS-COV-2 S1 spike protein in ELISA and western blotting. Recombinant antibodies were made from one patient's clonally expanded CSF plasmablasts. In addition, histological staining with these antibodies were performed in rat and human spinal cord sections to determine antigenicity. Immunoprecipitation was done with human spinal cord lysate and the protein target sent for liquid chromatography-mass spectrometry (LC-MS). To further understand the role of our recombinant antibodies, western blots, ELISAs and immunocytochemistry (ICC) staining were performed. 
Results:
Both patients CSF showed an antibody response to SARS-COV-2 S1 spike protein by ELISA. The recombinant antibodies did not react to  the  S1 spike protein by  ELISA or Western blot.  However, one antibody bound to rat spinal cord and another to human spinal cord sections. Immunoprecipitation of the human reacting antibody with spinal cord lysate yielded a target of glial fibrillary acidic protein (GFAP). Furthermore this antibody reacted strongly to GFAP by ELISA and weakly by Western Blot suggesting that it bound to a conformational epitope.  Additionally, an immunoprecipitation with the antibody reactive against rat spinal cord and iPSC-induced astrocyte lysate was performed, and the product sent for LC-MS, and the putative antigen identified as cytoskeletal keratin type II. 
Conclusions:

Our study shows that in patients with vaccination induced demyelinating disorders,  anti-SARS-COV-2 S1 spike antibodies may be detected in CSF.   Recombinant antibodies derived from CSF clonally expanded B-cells reacted with cytoskeletal keratin type II protein and GFAP.  However, further investigation with the antibodies needs to be performed to better postulate a mechanism for demyelination. 

10.1212/WNL.0000000000202604