All in the family. DNA encoding the Kunjin virus, a cousin of the West Nile virus, causes the muscle cells to make enough viral and boost immunity to ward off West Nile infections.
Researchers have developed a unique vaccine against the West Nile virus that puts the disease in mice. The vaccine, which uses a small cousin of the West Nile virus to stimulate the immune system, joins two other experimental vaccines that could one day prevent infection in humans.
The epidemic of West Nile has spread to 32 states, Mexico, and much of Canada. Although most people exposed to West Nile virus to escape unharmed, in 02 alone, the virus sickened 284 and killed 4156 Americans, causing brain infections. There are no drugs to banish the virus people, and to date no vaccine to prevent it. Several vaccine candidates have been developed, including a virus, yellow hybrid West Nile fever, which took place off the disease in monkeys, and a Nile virus hybrid Western-dengue has prevented in mice ( Science NOW March 5, 02). Virologists and Roy Hall Khromykh Alexander of the University of Queensland in Brisbane, Australia, instead working with a well-studied and harmless cousin of the West Nile virus called Kunjin virus.
Because the genome Kunjin virus is almost a carbon copy of the genome West Nile, and it causes only the mildest symptoms, it seemed like an ideal candidate for a vaccine. To make sure it was harmless, the researchers made a copy RNA to DNA virus genome and tweaked a gene to make it even safer virus. Low doses of the injected DNA in the mouse thigh muscles caused them to produce antibodies that neutralize both Kunjin and a virulent strain of West Nile virus in test tube experiments. Then the vaccine has passed the acid test: When the researchers injected what would have been lethal doses of West Nile virus directly into the brain of mice immunized, almost all have been protected
Thomas Monath of OraVax Cambridge, Massachusetts. , Company that developed a vaccine against yellow fever in the hybrid competition, called the work "elegant" but wondered whether the weakened virus would provoke an immune response strong enough to protect monkeys and human expansion. Diane Griffin virologist at Johns Hopkins School of Public Health, however, welcomed the new contender; because other vaccine candidates can not take place, "it is good to have other candidates in the wings."
Related Sites
CDC West Nile homepage
virus inserts West Nile from the US Department of Agriculture
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