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New vaccine may fight off infectious diseases


July 3, 1996
Web posted at: 12:30 a.m. EDT

From CNN Medical Correspondent Andrew Holtz

PHILADELPHIA (CNN) -- Fran Carroll took a seat in the doctor's chair and smiled as the doctor rattled off a list of questions.

"No adverse experience at all?" the doctor asked.

"Nothing," said Carroll, an HIV-positive patient who is one of the first people to be tested with a pioneering treatment known as a DNA vaccine.


The first version of the vaccine is made from snippets of genes from HIV, the virus that causes AIDS. The volunteers who have subjected themselves to the tests are HIV positive.

Researchers originally were testing to make sure the revolutionary technique was safe, but suddenly researchers found a bonus: The DNA vaccine often sparked immune system responses in patients, including antibodies to combat HIV.

David Weiner with the University of Pennsylvania Medical Center said doctors now have a new tool for developing and testing vaccines. (102K AIFF or WAV sound)


"It now can be examined and tested for a wide range of human applications in both infectious diseases as well as the cancer arena," Weiner said.

Despite the significant findings, researchers stressed that to this point the treatment is not an effective AIDS vaccine.

The so-called DNA vaccine differs from the typical vaccine, like polio, which contains a virus that is either killed or weakened. The typical vaccine introduces the foreign body to our immune system, enabling it to build up protection to fight off real infection.

The DNA vaccine, however, uses just a few genes of a virus. Tests in animals reveal that the genes slip into cells, which then appear to be infected. The immune system often responds more vigorously than it would to a typical vaccine.

For example, a DNA vaccine could offer longer-lasting protection than a flu shot that must be administered yearly.

Some doctors greet the new treatment warily.


"It is gene therapy," said Dr. Roy MacGregor with the University of Pennsylvania. "For that reason, there is a great deal of safety concern and caution."

Thus far, no safety problems have been identified in volunteers such as Carroll.

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