Classification of Inoue-Melnick virus into three antigenic types.

Antigenic analysis of Inoue-Melnick virus, formerly called SMON virus, showed that isolates from patients with subacute myelo-optico-neuropathy (SMON) in Japan, thus far tested, belonged to a single antigenic type (type 1). However, Inoue-Melnick virus isolates obtained so far in the United States chiefly from patients with multiple sclerosis could be classified into three types: type 1, type 2, and an intermediate type. At the present state of knowledge, the virus has not been proven to be the causative agent of disease, hence its provisional designation as IMV.