Scientists Find Gene Clue in Hunt for AIDS Vaccine

Wed Dec 8, 2004 06:02 PM ET

By Patricia Reaney

LONDON (Reuters) - Scientists said Wednesday they have identified key genes involved in the body's response to HIV, which causes AIDS -- a finding that could narrow the search for an effective vaccine against the deadly illness.

A vaccine is considered the Holy Grail in the battle against the global AIDS epidemic but efforts to find one have been hampered because of HIV's uncanny ability to mutate.

"We have narrowed down the focus of which particular genes are important in determining the outcome of HIV infection," said Dr Philip Goulder, of the Partners AIDS Research Center at Massachusetts General Hospital in the United States.

"It tells us where to look, what to put into a vaccine in broad terms, and perhaps what needs to be excluded."

He and his colleagues focused their research on genes called HLA-A, HLA-B and HLA-C which produce molecules that sit on the surface of cells. They tell immune system killer T-cells when new viruses are produced within an infected cell and should be destroyed.

The scientists said HLA-B genes are the key players in the body's response to infections, including HIV.

"HLA-B is where all the action is," Goulder told Reuters. "Most vaccines take no account of the fundamental biological differences between HLA-A and HLA-B genes. These may be critical to the success or failure of a vaccine."

In research reported in the science journal Nature, the scientists studied blood samples from 375 HIV-positive patients in South Africa. They discovered that how well a patient's immune system responded against HIV depended on their version of the HLA-B genes and had little to do with the other genes.

More than 560 versions, or alleles, of HLA-B have been identified.

"It is the responses that are generated through the HLA-B genes that are important," said Goulder.

The researchers also found that HIV positive mothers who have a protective version of HLA-B were more likely to survive and less likely to pass on the virus to their children.

"This study identifies the genetic background where the struggle between HIV and the human immune system response occurs," said Goulder.

"The findings will help in understanding precisely how the immune system can succeed or fail against HIV, a prerequisite for a rational approach toward design of an HIV vaccine."

About 38 million people worldwide, including 25 million in sub-Saharan Africa, are living with HIV/AIDS, according to the latest global report produced by the Joint United Nations Program on HIV/AIDS (UNAIDS).

Scientists believe even a partially effective vaccine could play an important role in reducing infections.

WASHINGTON (AFP) - A new antibiotic may speed up treatment of tuberculosis, the most deadly infectious disease in the world after AIDS, drugmaker Johnson and Johnson announced.

The treatment, tested in mice, appeared to be safe in a preliminary study in healthy humans, the drugmaker said.

"Scientists at Johnson and Johnson Pharmaceutical Research and Development have identified a novel anti-tuberculosis compound that works better and faster than the current standard of care in mouse models of TB infection," the company said in a statement.

The findings were published in the December 9 issue of Science Express, the online version of the journal Science, and will be published in the January 14 print edition.

The Johnson scientists worked with colleagues at the Swedish Institute for Infectious Disease Control in Solna, Sweden, and Pitie-Salpetriere School of Medicine in Paris.

The new drug, dubbed R207910, cleared TB infections from the lungs of mice better than a three-drug regime recommended by the World Health Organization, Johnson said.

"The drug acts through a novel mechanism of action, and is therefore active against all multi-drug resistant strains of TB tested so far," said Koen Andries, of Johnson.

Johnson said in a statement that no new anti-TB drugs have been developed in 40 years, while one out of three persons in the world is a carrier of TB. The company pointed out that TB has worsened the AIDS crisis, because HIV-infected people are likely to get the disease.

"That is the main reason why there is now such a resurgence of tuberculosis in countries that were previously hit by HIV," Andries said.

"The HIV epidemic has worsened the TB epidemic substantially."

Johnson said the new drug, when combined with others, could possibly reduce treatment times by as much as 50 percent.

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