NEW YORK (Reuters Health) - A live measles vaccine expressing West Nile virus (WNV) antigen protects mice against lethal challenge with West Nile virus, according to French researchers. “Potentially, this vaccine is able to induce full protection from WNV disease in humans as soon as 8-10 days after vaccination,” Dr. Frederic Tangy told Reuters Health.
Dr. Tangy from Institut Pasteur, Paris, and colleagues evaluated the efficacy of the widely used measles vaccine, engineered to express the secreted form of the E envelope glycoprotein of WNV, in protecting against WNV challenge in susceptible mice.
The recombinant vaccine induced specific anti-WNV antibodies at titers of 1:40,000 to 1:60,000 one month after the first inoculation, and titers of 1:500,000 to 1:900,000 one month after boosting, the authors report in the January 15th issue of The Journal of Infectious Diseases.
Mice that received the recombinant vaccine experienced no morbidity or mortality after inoculation with a lethal dose of WNV (one month after boosting), the team found, whereas control mice died within 3-4 days of lethal challenge with WNV.
Passive immunization also worked. Mice given as little as 2 microliters of serum from WNV-immune mice were protected from lethal WNV challenge, but all mice that received serum from control mice died within 11-12 days of the challenge.
“Mice were still fully protected at 6 months after vaccination (corresponding to a quarter of mouse life),” Dr. Tangy said. “A very high anamnestic memory response was raised by challenge at that time.”
Studies of the vaccine in primates are ongoing, Dr. Tangy said, with results expected later this year.
“The memory induced should last for at least 10 years,” Dr. Tangy concluded. “Such a vaccine would be able to prime memory in 95% of vaccinated individuals and could also be used locally to control WNV outbreaks.”
Source: J Infect Dis 2005;191:207-214. [ Google search on this article ]
MeSH Headings:Genetic Engineering: Genetic Techniques: Investigative Techniques: Analytical, Diagnostic and Therapeutic Techniques and EquipmentCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
