Researchers Test Vaccine to Curb Spread of AIDS

Researchers said Monday they may have come up with a new approach for an AIDS vaccine, one that would not prevent infection but might help stop the virus from being passed on.

The researchers worked with monkeys infected with an artificial version of HIV--the closest they can get to a human model. But they warned they are a long way from anything that might work in people.

“This holds promise for the development of a vaccine capable of seriously reducing viral replication and thus stemming the transmission of AIDS,” said Dr. Harriet Robinson, chief of microbiology and immunology at Yerkes Primate Center in Atlanta, who led the study.

“I think it has very high promise for humans,” she added in a telephone interview. “I’m excited by it, but we aren’t there yet.”

Robinson and a team of researchers across the United States created a hybrid virus from HIV and simian immunodeficiency virus, which infects monkeys. It is hard to infect other animals with HIV, which is very specific to humans, but this hybrid works well as a model for HIV infection, she said.

Robinson’s team genetically engineered a fowl pox virus so that it “expressed” four genes from HIV--thus producing proteins the immune system might recognize.

Tests prompted the production of antibodies, which help the immune system attack an invader. And it also got a “cell-mediated response”--meaning immune cells mobilized against the virus.

Writing in the journal Nature Medicine, Robinson’s team said they tried to infect their monkeys three times, but the vaccine controlled the infection.