Sialylation of the host receptor may modulate entry of demyelinating persistent Theiler's virus

Theiler's murine encephalomyelitis virus (TMEV) is a picornavirus of the Ca rdiovirus genus. Certain strains of TMEV may cause a chronic demyelinating disease, which is very similar to multiple sclerosis in humans, associated with a persistent viral infection in the mouse central nervous system (CNS) . Other strains of TMEV only cause an acute infection without persistence i n the CNS. It has been shown that sialic acid is a receptor moiety only for the persistent TMEV strains and not for the nonpersistent strains. We repo rt the effect of sialylation on cell surface on entry and the complex struc ture of DA virus, a persistent TMEV, and the receptor moiety mimic, sialyll actose, refined to a resolution of 3.0 Angstrom. The Ligand binds to a pock et on the viral surface, composed mainly of the amino acid residues from ca psid protein VP2 puff B, in the vicinity of the VPI loop and VP3 C terminus . The interaction of the receptor moiety with the persistent DA strain prov ides new understanding for the demyelinating persistent infection in the mo use CNS by TMEV.