The Human Immunodeficiency Virus is notorious for the rapid rate of mutation which makes it a constantly moving target for those trying to develop a vaccine. In a massive collaboration funded by the National Institute of Health, scientists have established a timeline of HIV mutations that cause the immune system to begin antibody production. This gives the researchers a new avenue to explore toward creating an HIV vaccine. The results were published in Nature.
Since HIV first emerged in the Congo, over 75 million people have been infected worldwide. Of those, almost 36 million have died from complications. Those who are currently infected with the virus can receive treatment and live a long, healthy life; a sharp contrast to the imminent death sentence an HIV/AIDS diagnosis was at the beginning of the epidemic. However, treatments are still incredibly expensive and must be strictly maintained over the course of a lifetime. Immunologists continue to work toward a vaccine that would prevent anyone from acquiring the virus in the first place.
Though HIV frequently mutates, the researchers found that a binding site, named V1V2, has remained fairly conserved and is susceptible to antibodies created by the immune system. Antibodies that are able to neutralize certain strains of the virus occur in about one-fifth of all HIV-infected individuals. The ability to replicate certain forms of those antibodies are believed to be the key to creating an HIV vaccine.
The team was able to identify twelve somatically-related antibodies (VRC26) that had been created by the immune system in blood samples from an HIV+ volunteer only known CAP256. The breakthrough came when they discovered that even after the virus mutated and changed a few times, the antibodies were still able to neutralize a wide range of strains.
Studies like this have been attempted before, but scientists did not have access to the earliest forms of the virus that caused the immune system to begin antibody production. With that factor as an unknown, vaccine discovery could not occur. For patient CAP256, blood samples had been taken weekly for over 3 years, beginning just four weeks after the infection. This allowed scientists to monitor the progression of the virus and the antibodies and study their co-evolution.
It took over two and a half years for the antibodies to mature enough to be able to neutralize isolates of the virus. The researchers believe they now have a solid timeline to work from and can begin to develop artificial copies of the antibodies from different milestones during its progression.
Though the antibodies do not neutralize all strains of HIV, it does affect many of them. The researchers are currently trying to use those antibodies to develop a vaccine. After the vaccine has been tested for safety and efficacy with animal models, they will seek trials using uninfected humans.