Wistar studies resistance to HIV among some sex workers
Statistics show that over 50 pecent of people who have HIV-1 infections are women. Even though commercial sex workers have a higher risk of developing HIV infections due to their regular exposure to HIV, among some of the workers living in regions that have especially high HIV rates there remains a small group of female sex workers who consistently test negative for the virus.
This small group reports the same sexual activity and low condom use as do the workers who have HIV infections. It is unclear why the women continue to have HIV protection when they do not show the common immune responses against the virus.
Scientists have studied this phenomenon to determine if there may be preventive behavioral and vaccine methods that can decline HIV infections. While the answer to this question has been a mystery to researchers for many years, Wistar Institute scientists suggest that the women’s tissue and immune systems react differently compared to how vaccines generate immune responses.
"Making the link between sex work, changes in immune state and semen exposure gives us an important piece of information that will hopefully help us establish whether or not chronic semen exposure and its effects on to the female reproductive tract can contribute to HIV resistance in sex workers that remain uninfected despite low condom use," Dr. Luis J. Montaner, director of Wistar's HIV-1 Immunopathogenesis Laboratory and lead author of the study, said. "It also clearly indicates that women are equipped to activate mechanisms of resistance due to sex itself, which we did not expect to find at the start of this research."
Data from the study demonstrates that the women’s ongoing exposure to semen alters the vaginal and cervical microenvironment. This serves to heighten their resistance to the virus.
"It is important to note that the study does not make a case for sexual intercourse without a condom, as doing so will increase the overall risk of HIV infection and other sexually transmitted diseases," Montaner said. "Instead, this study identifies unexpected effects that long-term semen exposure may have on the cervix and vagina that may lower but not remove the likelihood of infection."