Gene That Prevents HIV From Replicating in Monkeys Could Play Role in New Treatment Options for Humans, Study Says
A gene called TRIM5-alpha that prevents HIV from replicating in rhesus monkeys could provide new treatment options for humans and could help prevent HIV-positive humans from developing AIDS, according to a study published in Jan. 11 issue of the journal Current Biology, Reuters reports. Because monkey cells are more difficult than human cells to infect with HIV in a laboratory setting, scientists suspected that monkey cells differed from human cells in a way that prevented infection. Dr. Jonathan Stoye, head of virology at the British National Institute for Medical Research, and colleagues studied differences between gene products of the human and monkey TRIM5-alpha genes. The researchers "pinpointed" a specific change in an amino acid that is responsible for blocking HIV and discovered that they could make human cells resistant to HIV by substituting a human amino acid with a monkey-derived amino acid, according to Reuters (Reaney, Reuters, 1/10). Stoye said that if humans' TRIM5-alpha genes had undergone that minimal change, "we would probably never have had AIDS in the first place," adding, "The virus would probably never have entered the human population. But we did not, so HIV took hold." Stoye said that he and his colleagues over the "next couple of years" will try to develop a form of gene therapy that could limit HIV's impact on the human body, according to London's Guardian (Boseley, Guardian, 1/11). In a study published in the Feb. 26, 2004, issue of the journal Nature, researchers from the Harvard University Dana-Farber Cancer Institute and Harvard Medical School found that TRIM5-alpha is effective at preventing HIV infection by keeping the virus from shedding its capsid, which is the first step in HIV replication after the virus has entered a cell (Kaiser Daily HIV/AIDS Report, 2/26/04).
"The discovery has significant implications for the development of effective gene therapy to combat AIDS," Stoye said, adding, "In theory, it should be possible to take cells from an HIV-infected individual, make them resistant to HIV infection with the modified gene and reintroduce them into the patient. These cells could then block progression to AIDS. Alternatively, we could seek for drugs that activate the human gene against HIV." Christopher Gadd, editor of HIV & AIDS Treatments Directory, said, "What is particularly exciting is that the researchers have identified that changing just one amino acid 'building block' in one protein can switch a cell from susceptible to insusceptible to long-term HIV infection," adding, "However, it is important to stress that any therapeutic benefits that may arise from this research are unlikely to be felt for many years." Jo Robinson, a senior treatment specialist at the Terrence Higgins Trust, said that gene therapy is a "promising" approach that could produce long-term results, adding, "We should stress that although this research is important we are still a long way from it having a practical application for people with HIV. There is still no cure for HIV and no vaccine" (BBC News, 1/10).