Identification of coronin‐1a as a novel antibody target for clinically isolated syndrome and multiple sclerosis

Recently, we identified the mimotope UH ‐ CIS 6 as a novel candidate antibody target for clinically isolated syndrome ( CIS ) and relapsing‐remitting ( RR ) multiple sclerosis ( MS ). The purpose of this study was to further validate UH ‐ CIS 6 as an antibody target for CIS and MS and to identify the in vivo antibody target of UH ‐ CIS 6. First, a UH ‐ CIS 6 peptide ELISA was optimized. Next, we investigated the antibody response toward UH ‐ CIS 6 in cerebrospinal fluid ( CSF ) from patients with CIS ( n  = 20), MS ( n  = 43) and other neurological diseases ( n  = 42). Immunoprecipitation of anti‐ UH ‐ CIS 6 antibodies on a normal human brain lysate was performed to identify the in vivo antibody target of UH ‐ CIS 6. The cellular expression of an in vivo candidate target was investigated by immunohistochemistry using MS brain tissue sections. Antibody reactivity toward UH ‐ CIS 6 was detected in a significantly increased proportion of CSF samples from CIS and RR ‐ MS patients as compared with neurological controls ( p  = 0.046). We identified and confirmed coronin‐1a as the in vivo antibody target for UH ‐ CIS 6. Furthermore, coronin‐1a was expressed by T cells and macrophages in an active MS lesion. Together, these results demonstrate that coronin‐1a is a novel antibody target for CIS and MS .