[SSPE virus and pathogenesis].

Subacute sclerosing panencephalitis (SSPE) is caused by particular mutants of measles virus, which are often referred to as SSPE virus. SSPE virus is characterized by (i) the inability to produce infectious viral particles, (ii) the neuropathogenicity in animal models as well as in humans, and (iii) the prolonged persistence in vivo over many years. The viral genome exhibits particular mutations, called biased hypermutation, most notably in the M gene, followed by the F and H genes. Consequently, the M, F and H proteins are mutated, which is thought to account for the characteristic features of SSPE virus. The possible mechanism of long-term persistence of the virus after the recovery of measles is also discussed.