LYMPHOCYTE RECOGNITION ELEMENTS ON THE VP1 PROTEIN OF THEILERS VIRUS

Theiler's virus is a murine picornavirus that persists in the central nervous system in susceptible mouse strains, and gives rise to immune mediated demyelinating disease. Antiviral CD4 T cells are necessary to protect from overwhelming virus replication in the acute phase of the disease, and are thought to act by stimulating the antibody response. The present study used overlapping synthetic peptides to map the loca tion of epitopes recognized by CD4 T cells. One T-cell epitope was ide ntified between amino acids 33-47 of VP1, which was recognized by viru s-reactive T cells. 'Cryptic' epitopes were also present within VP1 at postitions 153-167, 166-180, 225-239 and 233-247. A linear B-cell epi tope was identified in the C-terminal region 225-276. Immunization of CBA mice with inactivated virus, but not peptides containing VP1 B- or T-cell epitopes, reduced the virus titre in the CNS in the acute phas e of the disease.