ERVW-1 and multiple sclerosis: Starting from the recognized involvement of envelope protein pathogenic HERV-W (pHERV-W) ENV (formerly multiple sclerosis-associated retrovirus [MSRV]-ENV) in the pathophysiological process of multiple sclerosis (MS) and type 1 diabetes (T1D) [162,163], the monoclonal antibody (mAb) temelimab, also known as GNbAC1, which selectively binds with high affinity to the extracellular domain of the pHERV-W Env, was selected for clinical development [162].