Children's Hospital working on new HIV vaccine

May 18, 2009 2:48:53 PM PDT
Like a general whose direct attacks aren't working, scientists are now trying to outflank the HIV/AIDS virus.

Dr. Philip Johnson of the Children's Hospital of Philadelphia is studying a new approach to prevent HIV.

Most vaccines are made with a weakened virus, which hasn't worked to stop HIV. But that approach has been largely unsuccessful.

So Dr. Johnson's vaccine uses genetic material to block the infection, but bypass the immune system.

So far, it's worked in mice and monkeys, they reported Sunday in the online edition of the journal Nature Medicine

"We used a leapfrog strategy, bypassing the natural immune system response that was the target of all previous HIV and SIV vaccine candidates," Johnson said. HIV, or human immunodeficiency virus, causes AIDS in people. The closely related simian virus, or SIV, affects monkeys.

"Some years ago I came to the conclusion that HIV was different from other viruses for which we were trying to develop vaccines and we and might not ever be able to use traditional approaches," Dr. Johnson said.

He told Action News, "It has passed a very stringent test, we were able to prevent infection in monkeys. Our goal and our belief is this is transferrable to humans and should in fact work in humans if we can prove it's a safe approach."

That doesn't mean an AIDS vaccine for people is in the wings, Johnson said. Years of work may lie ahead before a product is ready for human use.

Nevertheless, the report was welcomed by Dr. Beatrice Hahn, an AIDS researcher the University of Alabama at Birmingham, who was not part of Johnson's team. "It basically shows there is light at the end of the tunnel," she said in a telephone interview.

"It shows thinking outside the box is a good idea and can yield results, and we need perhaps more of these nonconventional approaches," she added.

According to the International AIDS Vaccine Initiative, AIDS is one of the most devastating pandemics. More than 20 million people have died so far and about 33 million are living with HIV. The Center for Disease Control and Prevention last year estimated there are about 56,000 new HIV infections annually in the United States.

The research was supported by the National Institute of Allergy and Infectious Diseases.

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