A study comparing vaginal secretions from HIV-1 resistant and non-resistant Nairobi sex workers may have important implications for HIV prevention research. The paper, published in the Journal of Proteome Research, found that proteins known to inhibit HIV are over-expressed in the genital secretions of HIV-resistant sex workers, while others known to stimulate immune response are under-expressed.
The idea that immune-response stimulants are under-expressed in HIV-resistant subjects may seem counter-intuitive, but as Adam Burgener, a post-doctoral fellow at the University of Manitoba, and one of the paper’s authors, explained, the results actually makes sense.
“In the case of HIV [lower expression of proteins that stimulate immune-response] is actually beneficial because HIV infects immune cells. So if you have less immune cells present, then perhaps HIV doesn’t have as many targets to infect,” Burgener said.
Researchers at the University of Manitoba and the University of Nairobi have been collaborating on research of infectious diseases since 1980. The women who participated in the study are part of a larger cohort of 2,000 commercial sex workers, more than 140 of who have been characterized as being relatively resistant to HIV-1.
Burgener and his colleagues’ work is being praised by many of those interested in the science of HIV prevention, including Anna Forbes, Deputy Director of the Global Campaign for Microbicides.
“We’ve known about the phenomenon of the [HIV-resistant] Nairobi sex workers for a while…but it is very interesting to see more research being done on it. I think what it tells us is that there is a great deal that we still need to understand about the ecology of the vagina, about how the vagina actually works, and how the vagina actually defends itself,” said Forbes.
Burgener was also enthusiastic about the implications this research may have on the advancement of tools for the prevention of HIV transmission.
“Anything that we find can certainly aid in the development of new microbicides or better ones, since this is a natural model of resistance against HIV,” Burgener said.
Microbicides – gels, creams, foams, and depositories developed for physical application inside of the vagina or the rectum to halt the transmission of HIV – have been in development for some time now. According to Forbes, 50 candidate products have been identified thus far; three are in late-stage efficacy trials. However, none have yet been proven to halt the transmission of HIV.
Forbes highlighted the importance of Burgener’s research, saying that the development of an effective microbicide could significantly help women.
“The right to protect oneself from HIV is a human right, and right now, for millions of women around the world, it’s a human right that they have no ability to realize because insisting on condoms is not an option, and insisting on abstinence is not an option,” Forbes said.
The next step, according to Burgener, is to replicate the study on a larger scale in order to ensure broader validity among HIV-resistant women, and to confirm that the differential expression of these proteins is not confined to these specific cases. Currently, 600 women are involved in a follow-up study.
“Once we do that, then we’ll tackle the hard biology – looking at how exactly these proteins may be inhibiting HIV, if at all. Trying to figure that out will be years of work,” Burgener said.
What’s more, Forbes explained that this kind of research could be happening in more labs and could be moving at a quicker pace if more funding was directed toward it.
“We would like to see much more research going on,” she said. “Women’s health has always been a very under-served area, and microbicide research, because it compounds the stigma of women’s health with the stigma of HIV, is even more under-served.”