US researchers have developed a mouse model that can be used to test the efficacy of much-needed methods to prevent transmission of HIV, the virus that causes AIDS.
J. Victor Garcia, a researcher at the University of Texas Southwestern Medical Center in Dallas, says that such mice can be used for animal testing of pre-exposure antiviral drugs that have been designed to protect against HIV infection.
He says that such mice also provide a new way of evaluating microbicides and other prevention approaches that have generally required testing in macaques, using viruses that are related, but not identical, to HIV.
The development by Garcia's team involved "BLT" mice, which have been transplanted with human blood cells, liver, and thymus tissue.
During a study, the researchers found that human cells necessary for HIV infection distributed themselves in the female reproductive tract of BLT mice, rendering them susceptible to vaginal infection with HIV.
They also observed that infection spread to other organs in a way similar to the course of HIV infection in humans.
Another significant finding of their study was that vaginal infection could be blocked by treating the mice with antiretroviral drugs that are currently being evaluated as pre-exposure prophylaxis (PrEP), a possible means of HIV prevention in humans at risk for sexual exposure to HIV.
Garcia's findings support the promising results of PrEP studies from established, but costly, macaque models.
The researchers, however, concede that the reliability of the BLT mouse as a predictor of HIV prevention in humans can be determined only through a comparison of animal experiments to actual human trials.
Barbara Shacklett, an expert at the University of California Davis, has discussed the paper in a related perspective article titled 'Can the New Humanized Mouse Model Give HIV Research a Boost?'.
"(At this stage) the most prudent approach is to consider the new humanized rodents and the more established, nonhuman primate models as complementary systems, both of which can yield useful information but neither of which is infallible," says Dr. Shacklett.
The new findings have been reported in PLoS Medicine.