Jefferson immunology researchers halt lethal rabies infectio...( (PHILADELPHIA) While rabies an ancie...),Health

(PHILADELPHIA) While rabies, an ancient scourge that still kills 70,000 every year in developing countries worldwide can be combated with a series of vaccines today, it nearly is always fatal when it reaches the brain.

But now, immunology researchers at the Kimmel Cancer Center at Jefferson have shown how a type of bat rabies infection can be prevented in mice even after the virus reaches the brain, when it is most lethal. They found that by opening the central nervous systems (CNS) protective blood-brain barrier, powerful infection fighting substances can swarm in, essentially driving off the invading virus. A better understanding of the process, they say, may lead to improved treatment for late-stage rabies infections in humans.

The findings indicate that delivering immune system effector cells T and B cells to the CNS can reverse an otherwise lethal rabies infection even after the virus has reached the brain, says D. Craig Hooper, Ph.D., associate professor of cancer biology at Jefferson Medical College of Thomas Jefferson University in Philadelphia, who led the work. While thats not a practical way to help infected humans, finding a method to open the blood brain barrier may be crucial to saving a person who is already showing clinical signs of rabies infection, where a vaccine is useless. They report their work in the Journal of Virology.

Halting rabies in the brain

In earlier work in mice, Jefferson doctoral candidate Anirban Roy found evidence suggesting that despite an immune system response, cells that are responsible for clearing the rabies virus from the CNS never cross the brain barrier. The researchers wanted to know why the barrier fails to open, and if mice were dying because the infection didnt get cleared, then would opening the barrier result in the animals surviving.

The scientists compared silver-haired bat rabies infections in two strains of mice: PLSJL mice and 129/SvEv mice. They fo
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