March 17, 2009
HIV-positive people who do not develop AIDS and do not require antiretroviral medication could provide insight for new strategies in vaccine development, according to a study published Sunday in the journal Nature, London's Independent reports. Michel Nussenzweig -- head of Rockefeller University's Laboratory of Molecular Immunology and author of the study -- said his research aimed to harness natural mechanisms to target HIV rather than use synthetically produced antibodies, some of which have failed in earlier HIV vaccine trials.
For the study, Rockefeller University researchers examined antibodies present in the blood of six long-term HIV survivors who appeared to have a degree of natural immunity to the virus (Connor, Independent, 3/16). The researchers isolated 433 antibodies from the patients, all of which targeted HIV's protective outer coating, or "envelope." The researchers then cloned the antibodies and observed which elements of the envelope each antibody targeted and how effectively it neutralized HIV. During the research, Johannes Scheid, a doctoral student at Rockefeller University, identified a new structure on the HIV envelope that scientists previously had not recognized as an antibody target. Although the researchers determined that each antibody individually had a weak effect on HIV, they also found that the antibodies as a group effectively targeted the virus (PA/Google.com, 3/15). In addition, the researchers determined that a prototype vaccine developed from several of the antibodies can prevent the growth of HIV in human cells in a test tube.
Nussenzweig said the study identified "many different antibodies that individually have limited neutralizing ability but together are quite powerful." According to Nussenzweig, only about one in every 1,000 HIV-positive people produces the neutralizing antibodies. He said the research attempts a new approach to HIV vaccine development by "copying what exists in nature and that we know can work because of the long-term survivors." He added, "Instead of inventing something that doesn't exist, it's trying to copy something that does exist." Nussenzweig said the study's results "should make people think about what an effective vaccine should look like." According to the Independent, the researchers next plan to conduct further trials of vaccine candidates on laboratory animals and human volunteers.
Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, or sign up for email delivery at www.kaisernetwork.org/dailyreports/hiv. The Kaiser Daily HIV/AIDS Report is published for kaisernetwork.org, a free service of the Kaiser Family Foundation, by The Advisory Board Company. © 2009 by The Advisory Board Company and Kaiser Family Foundation. All rights reserved.