Continued Semen Exposure May Amp Up HIV Resistance

It’s well-known that unprotected sex increases your chances of contracting the human immunodeficiency virus (HIV) and other sexually transmitted diseases, but a surprising study involving sex workers found that continued semen exposure may actually help the body build up resistance.

Before diving into the data, the researchers from The Wistar Institute stressed that the analysis doesn’t make a case for unprotected sex — because that behavior ultimately leads to a higher risk of infection. However, it does point out changes in the body that take place as a result of the constant exposure. The team analyzed sex workers in Puerto Rico, due to their chronic exposure.

The cohort included 50 women with a median age of 35.5 who had been working in the industry for at least three years. All of these women were tested and came back negative for HIV. They were compared with 32 women from the area who reported low semen exposure.

Three key findings came out of the analysis published in Mucosal Immunology. For one, we already know that the HIV virus thrives in activated immune systems, and as it turns out, the women with chronic exposure to semen had lower rates of immune activation in the blood and mucosal tissue.

Next, the women also had enhanced expression of the signaling proteins called interferon ε in epithelial cells. These proteins are responsible for protecting the female reproductive tract from viral and bacterial infections.

In addition, the researchers found that the higher the number of sex incidences without a condom, the more the cell expressions were enhanced. Lastly, there were lower levels of expression at the parts in the mucosal tissue which the HIV virus has to infect, like CD4 and Nucleoporin 153.

“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,” lead author Luis Montaner, DVM, DPhil, the Herbert Kean, MD, family professor at The Wistar Institute, said in a news release.

The findings suggest that long-term semen exposure on the cervix and vagina may lower the likelihood of infection, however, it does not take away the risk completely.

“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,” Montaner said.

Again, the study does not advocate risky behavior. It merely demonstrates how immune responses can change as a result of exposure.