Hi! Long time no post. Apparently, trying to finish a PhD and plan a wedding at a same time is not a good idea =P

Wanted to share a cool paper published online today in PNAS, whichshows that our immune system may be forcing HIV to evolve to a less virulent form. The ability of HIV to bind and kill our cells relies on the specific structure/shape of the HIV proteins. When the immune system learns to recognize these proteins, HIV is forced to evolve or perish. Fortunately, that means that sometimes the virus loses some of its ability to function.

(HIV in green, growing from an immune cell).

Researchers found evidence of this when they compared HIV infected individuals in Botswana versus South Africa. Importantly, the epidemic started earlier in Botswana, a higher proportion have been infected with the virus, and there has been longer use of antiretroviral treatments (ART). They found that in patients in Botswana, HIV had evolved to evade the immune system, but was unable to replicate as well. They also hypothesize that this same effect can be achieved with wide spread ART usage, and their model predicts that usage of the drugs can result in a milder virus.

Of course, that doesn't mean HIV is harmless, and it would take decades for significant crippling to be seen. Still, small changes in virulence can improve patient's chances at fighting off the virus. Plus, it is amazing to see evolution in action!