Scientists find immune responses, genetics play a role in HIV risk

In order to learn what aspects of a potential HIV vaccine are helpful in reducing an individual's risk of contracting the virus, researchers from the National Institute of Allergy and Infectious Diseases recently explored the differences between laboratory primates that were protected against the virus versus those in which the vaccine was not effective.

The scientists gave a group of more than 120 monkeys a newly developed vaccine, in addition to 12 doses of the primate form of the HIV, called the simian immunodeficiency virus (SIV). The researchers said that they injected the virus rectally to simulate the means by which many humans acquire HIV.

In monkeys that were protected by the vaccine, the results showed that these test subjects had increased activation of white blood cells known as helper CD4+ T cells. The findings also indicated that genetic factors contributed to the efficacy of the vaccine, since many primates who did not subsequently acquire SIV had duplicate copies of a specific gene.

Investigators noted that their findings support evidence that neutralizing antibodies are an important part of the immune response needed to prevent HIV infection.