Rapidly Evolving HIV Gene Making Vaccine Research Difficult

Across the globe, approximately 33 million people are HIV-positive. While antiretroviral drugs have been able to keep millions of patients relatively healthy and alive, over 25 million deaths can be attributed to AIDS since its inception in the 1980s. For years, researchers and scientists have devoted their lives to developing drugs and vaccines to help control and, hopefully, one day cure the virus. What is making the prospect of a cure or vaccine more challenging, however, is the fact that as HIV spreads across the globe it is constantly mutating and adapting within large populations to stop triggering the immune system.

For years, researchers were aware that HIV would mutate and alter within people in order to discover new ways to attack the cells. A new study recently published in the journal Nature, however, is showing that these changes that allow the virus to attack in new ways is being spread at an alarming rate to bigger populations. This study was led by an immunologist from Oxford University, Philip Goulder, who stated, “What was previously clear is the virus could evolve within each infected person but that doesn’t really matter from a vaccine perspective if the virus at the population level is staying the same. The implication is that once we have found an effective vaccine, it would likely need to be changed to keep pace with the rapidly evolving virus.”

Currently, HIV/AIDS researchers and scientists are struggling to find a vaccine that would prevent the infection from ever taking hold. They are also looking into therapeutic vaccines for HIV; these are vaccines that would keep the virus at bay enough so that an infected patient would be less likely to transmit the virus to others. Goulder states, “The process of the virus adapting is happening before our eyes at quite a speed, and it is something we need to take into account when making our vaccines.”

Once infection occurs, HIV attempts to attack the human body’s immune system. Like with any other virus, HIV is unable to replicate on its own; instead, it must penetrate and take over a cell that will enable it to replicate. In order to take over a cell like this, HIV has to bypass many genes. One of these immunity genes is named HLA. The research team which was comprised of scientists from both Japan and Australia studied close to 3,000 infected patients. They analyzed the virus as well as their HLA genes. In some patients, this HLA gene seems to be more protective. Researchers concluded that those patients who had the more protective genes were also hosts to the HIV version that had mutated to a point that it could dodge the immune responses that HLA directed.

Goulder felt this was substantial evidence of HIV mutating amongst large populations; thus, the “escape mutation,” as it has been coined, is popping up in larger populations of those patients infected with HIV. Goulder states, “We saw similar effects in every mutation that we looked at. This shows that HIV is extremely adept at adapting to the immune responses in human populations that are most effective at containing the virus.”