HIV Mutates ‘Incredibly Rapidly,’ Study Says; Findings May Aid Vaccine Research
HIV mutates its outer protective coating "at an incredibly rapid rate" in order to outsmart human antibodies, which are responsible for recognizing and destroying invading pathogens, according to a study published in the March 18 Proceedings of the National Academy of Sciences, the Wall Street Journal reports (Regalado, Wall Street Journal, 3/18). Therefore, antibodies may "drive" HIV mutation, according to the study. Researchers led by Douglas Richman of the Veterans Affairs San Diego Healthcare System and University of California-San Diego School of Medicine used new technology developed by San Francisco-based biotechnology company ViroLogic to clone HIV from the blood plasma of HIV-positive patients and combine it with luciferase, the enzyme in fireflies that emits light. The glowing enzyme allowed the researchers to track the replication of the virus. By studying the virus in antibody-containing blood plasma, the researchers isolated the effects of antibodies on the virus, independent of white blood cells and other immune system components. The researchers found that patients with HIV quickly develop a strong antibody response to the virus. However, that response exerts a "very strong selective pressure on the virus," causing it to continually mutate in order to evade the neutralizing antibodies. The virus consistently mutated faster than the antibody response, rendering the antibodies ineffective. "The bad news is that the virus is always staying a step ahead, and the neutralizing antibody response can't control it," Richman said (Veterans Affairs release, 3/17). This rapid mutation has been the "biggest challenge to developing drugs or vaccines," Gary Nabel, director of the vaccine research center at the National Institute of Allergy and Infectious Diseases, said. However, the findings may help open a path toward developing more effective vaccine strategies, such as vaccines that target those portions of the virus that are unable to undergo rapid mutation, Richman said (Wall Street Journal, 3/18).This is part of the KHN Morning Briefing, a summary of health policy coverage from major news organizations. Sign up for an email subscription.