AIDS researchers thought they were studying a cell ally in the fight against HIV. The molecule called RANTES, appears to delay the onset of disease. But now RANTES appears to be like two face as they come. Although the researchers tested the molecule slows AIDS, they also discovered that it makes them more likely to invite HIV first cells.
Three related molecules are known to inhibit the spread of HIV from cell to cell. All of these, including RANTES, are immune system molecules called chemokines. Test tube studies have shown that these molecules block the virus from infecting cells both in competition with HIV for entrance doors in T cells and somehow decreased the number of receptors available for HIV to hang.
RANTES comes in a few varieties genetically determined. To see if these types influence a person's response to HIV, a team led by Philip Murphy of the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, analyzed data of immune cells from a study being called the Multicenter AIDS Cohort study (MACS) conducted in Chicago, Los Angeles, Washington, DC, and Pittsburgh. MACS has collected blood samples from the men to the risk of HIV infection for more than 15 years. The team compared 404 men who were infected at 123 men who remained HIV-free despite engaging in some of the same high-risk behaviors.
Murphy team divided the men into two groups, depending on the version of the RANTES gene they carried. The group with the G4 variant took about 2 years after infection with HIV develop AIDS than did the group with the G1 variant, the team reports in December 1 issue of the journal AIDS . In test tubes, the G4 gene variant produces more than RANTES version G1, supporting the idea that RANTES inhibits the progression of HIV and prevents the disease as well. But the news is not all good for men with G4 variant: They are about twice as likely to be infected with HIV as men G1
It is strange that a version of a gene appears to protect against HIV infection. but eventually allows the virus proliferates. Murphy does not know how to interpret the findings, and it is not alone. "It's weird," said chemokine researcher Robert Gallo of the University of Maryland, Baltimore; "I do not know of a study before which showed a molecule inhibiting HIV and helping at the same time it certainly is. a paradox."
Related Sites
The Multicenter AIDS Cohort Study
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