Genetic Research Yields Clues to HIV Responses

Two new studies unveil genetic links to the way the body responds to HIV, opening the door to potential new treatments or possibly an HIV vaccine, researchers say. Scientists at the Partners AIDS Research Center at Massachusetts General Hospital in Boston identified several key human genes'HLA-A, HLA-B, and HLA-C'that reside on the surface of immune system cells and instruct an immune system attack on other cells infected with HIV. A study of 375 HIV-positive South Africans found that how well a patient's immune system responded to HIV in the body depended on their version of the HLA-B genes. More protective versions of the gene led to better immune system control of the virus in the body. HIV-positive mothers with the protective version of the gene also were shown to be less likely to pass the virus along to their babies. 'These findings will help in understanding precisely how the immune system can success or fail against HIV, a prerequisite for a rational approach toward design of an HIV vaccine' says lead researcher Philip Goulder. Researchers in London reported in January having discovered that a single change in the human Trim 5 Alpha gene might block HIV replication in the body and prevent HIV-positive people from developing AIDS. The gene exists in both monkeys and humans, but a specific difference in a key protein on the gene enables the monkeys to control the simian version of HIV in their bodies. The researchers say genetic engineering that removes the human protein and inserts the simian version also could make human cells resistance to HIV infection. 'The discovery has significant implications for the development of an effective gene therapy to combat AIDS,' lead researcher Jonathan Stoye reports in the January 11 issue of the journal Current Biology. 'If you have HIV, this might be a form of therapy to prevent progression to AIDS.' More laboratory research, followed by animal tests and human trials, are planned.