CHIMERIC CDNA STUDIES OF THEILERS MURINE ENCEPHALOMYELITIS VIRUS NEUROVIRULENCE

Strain GDVII and other members of the GDVII subgroup of Theiler's muri ne encephalomyelitis virus are highly neurovirulent and rapidly fatal, while strain DA and other members of the TO subgroup produce a chroni c, demyelinating disease. GDVII/DA chimeric cDNA studies suggest that a major neurovirulence determinant is within the GDVII 1B through 1D c apsid protein coding region, although the additional presence of upstr eam GDVII sequences, including the 5' untranslated region, contributes to full neurovirulence. Our studies indicate that there are limitatio ns in precisely delineating neurovirulence determinants with chimeric cDNAs between evolutionarily diverged viruses, such as GDVII and DA.