DNA vaccine coding for Kunjin virus RNA protects mice against West Nile virus.

2003 NOV 5 - (NewsRx.com & NewsRx.net) -- A DNA vaccine coding for the full-length infectious Kunjin virus RNA protected mice against the New York strain of West Nile virus.

According to recent research published in the Proceedings of the National Academy of Sciences USA, "A plasmid DNA directing transcription of the infectious full-length RNA genome of Kunjin (KUN) virus in vivo from a mammalian expression promoter was used to vaccinate mice intramuscularly. The KUN viral cDNA encoded in the plasmid contained the mutation in the NS1 protein (Pro-250 to Leu) previously shown to attenuate KUN virus in weanling mice."

"KUN virus was isolated from the blood of immunized mice three to four days after DNA inoculation, demonstrating that infectious RNA was being transcribed in vivo; however, no symptoms of virus-induced disease were observed," said Roy A. Hall and colleagues at the University of Queensland in Australia. "By 19 days postimmunization, neutralizing antibody was detected in the serum of immunized animals. On challenge with lethal doses of the virulent New York strain of West Nile (WN) or wild-type KUN virus intracerebrally or intraperitoneally, mice immunized with as little as 0.1-1 microgram of KUN plasmid DNA were solidly protected against disease."

"This finding correlated with neutralization data in vitro showing that serum from KUN ...