AIDS researchers were encouraged last year when they found that people with a specific genetic defect appeared to be protected against infection by HIV. But a new discovery, reported in the March issue of Nature Medicine , indicates that this protection is not absolute. The report serves as a warning that no one is completely safe from infection.
a gay man with HIV infection, the white blood cells Robyn Biti, Graeme Stewart Westmead Hospital in Sydney, Australia, and colleagues say they found containing a defective copy of a protein critical surface CCR5, that the virus uses for entering the cells. Previous studies in nearly 3,000 people infected with HIV had failed to find a single person who had inherited mutated copies of the gene that produces the protein CCR5 from both parents. "Until this paper, many people thought it would be a never" `event," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID). "I'm not surprised that it happens and I'm sure that's not the only one we'll see. "
Last year, researchers from NIAID and also solved a mystery for ten years when they found that HIV uses a second set of proteins to enter immune cells. In addition to white docking receptor called CD4 blood cells, scientists found that HIV also enters the cells via receptors - such as CCR5 - normally reserved for immune messengers called chemokines. Researchers found that people who had been repeatedly exposed to HIV but remained uninfected had two copies of a defective CCR5 gene. The discovery suggested that this flaw has offered strong protection against the virus.
Stewart, immunologist, said that rather than refute the earlier work, the new data simply add the complexity of history. CCR5 must remain "a very important goal for vaccines and medicines," he said, noting that they found one person with dual CCR5 defect in 300 people studied so far, but a case is nevertheless disturbing.: topic - who first tested positive for HIV 5 years ago - is already showing signs of immune damage against HIV the Australian team is trying to identify the strain of the virus. man to see how it compares to other HIV strains that require CCR5 to slip into immune cells.
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