Infectious cDNA clones of the DA strain of Theiler's murine encephalomyelitis virus.

The DA strain and other members of the TO subgroup of Theiler's murine encephalomyelitis viruses cause a persistent demyelinating infection, whereas the GDVII strain and other GDVII subgroup strains cause an acute lethal polioencephalomyelitis. We generated an infectious DA cDNA clone inserted into a transcription vector. Virus derived from transfection of transcripts produced a demyelinating disease indistinguishable from that of wild-type virus. The infectious clone provides a critical reagent for the production of interstrain recombinant viruses to help identify genetic loci responsible for the biological activities of the strains.