Systematic search for HIV immunity proposed.
A coalition of scientists aims to kick-start the stalled search for a vaccine against the human immunodeficiency virus (HIV). The researchers will mine the genomes of HIV-positive patients from many countries in the hope of finding ways to help the immune system fight HIV.
Scientists have been trying to figure out for years why some people are less susceptible to HIV than others. Studies on specific groups of patients such as Kenyan prostitutes have identified a handful of natural genetic variations that influence susceptibility to the infection. Leaders of the coalition now plan to combine data from many of these groups, to scan the whole genome of each patient instead of particular genes, and to focus on patients who have been tracked since the early days of their infection.
“The past 10 or 15 years of genetic work on HIV cohorts has been pretty painful,” says Amalio Telenti of the University of Lausanne in Switzerland, an organizer of the initiative. “This is a whole new ball game.”
The coalition, called EuroCHAVI, will include data from 600 patients in seven European countries and Australia, and will be funded by the Center for HIV/AIDS Vaccine Immunology (CHAVI), based at Duke University in Durham, North Carolina. CHAVI investigators also plan to set up study groups in Africa.
The scientists will look for differences between patients at hundreds of thousands of specific locations in the patients' genomes, hoping to find variations that influence how well people control the virus early in their infection. Identifying the genes involved should yield clues to how to design a better vaccine.
Large genetic studies are already under way for other conditions, including malaria and tuberculosis. But such an approach is more difficult with HIV because it cannot be studied in entire families, making it much harder to track inherited variations. The new studies have only become possible because of the recent construction of the HapMap, a catalogue of sites of variation in the human genome that was published last year (International HapMap Consortium Nature 437, 1299–1320; 2005).
Even so, it's still a gamble that the whole-genome studies will yield results. “There's no guarantee that this approach is going to work — it's very much a betting game, like anything else we do,” says Sunil Ahuja, a clinical researcher at the University of Texas Health Science Center in San Antonio, who is not involved with the EuroCHAVI study. “But you've got to take a shot.”
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Nature Medicine (2006)