NIH-Led Scientists Find Antibodies that Prevent Most HIV Strains from Infecting Human Cells

By Laura Sivitz Leifman, National Institute of Allergy and Infectious Diseases, NIH

Scientists have discovered two potent human antibodies that can stop more than 90 percent of known global HIV strains from infecting human cells in the laboratory. The scientists also have demonstrated how one of these disease-fighting proteins accomplishes this feat. According to the scientists, these antibodies could be used to design improved HIV vaccines, or could be further developed to prevent or treat HIV infection. Plus, the method used to find these antibodies could be applied to isolate therapeutic antibodies for other infectious diseases as well.

Led by a team from the NIAID Vaccine Research Center (VRC), the scientists found two powerful antibodies called VRC01 and VRC02 in an HIV-infected individual's blood. They discovered the antibodies using a probe they developed that homes in on the specific cells that make antibodies against a very vulnerable spot on HIV.

International AIDS Conference Day 3: Research Highlights

by Dr. Ron Valdiserri, Deputy Assistant Secretary for Health, Infectious Diseases, U.S. Department of Health and Human Services

Dr. Ron Valdiserri

Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, shared the latest scientific information with the conference delegates about the actual steps that the human immunodeficiency virus (HIV) takes when it makes contact with the human genital tract (through exposure to semen or vaginal secretions) which result in infection.Understanding, in detail, the early steps taken by the virus to establish infection is very important because it provides scientists with targets for the development of new drugs and potential vaccine candidates. Recent work has identified a special subset of CD4+ cells that are especially susceptible to HIV infection. With this discovery, scientists can now begin to develop strategies to block the virus, with the hope that such treatments could, in the future, successfully prevent HIV infections.

Dr. Everjoice Win , the Head of Women’s Rights at ActionAid International in Zimbabwe, spoke on the critical issue of gender-based violence against women and girls. She emphasized why it is essential to understand how violence and the fear of violence can impact all aspects of HIV/AIDS prevention, diagnosis, and treatment programs for women and girls. Dr. Win urged policy makers and leaders around the world to recognize “women’s rights” as human rights and urged better surveillance of gender-based violence and improved interventions for preventing it.

Tuesday afternoon, Drs. Quarraisha and Salim Abdool Karim, two well-known AIDS researchers from South Africa, released the results of their long- awaited study on a vaginal gel containing the antiretroviral drug, tenofovir. For the first time ever, a vaginal gel has been shown to significantly reduce the transmission of HIV. This landmark study, which enrolled nearly 900 South African women, was shown to reduce HIV transmission by 39%--compared to a placebo gel that did not contain the antiretroviral drug.This announcement was widely acclaimed by conference delegates as a significant step forward in HIV prevention for women around the world.

Watch a video recording of today's opening plenary .

Renewed Hope for an HIV Vaccine

By Dr. Carl W. Dieffenbach

Carl W. Dieffenbach, Ph.D

In late September, the U.S. federal government announced news on HIV vaccine research that sparked interest around the world. A trial called RV144, or the Thai HIV vaccine clinical trial , showed that the experimental vaccine regimen was safe and about 31 percent effective in preventing HIV infection. Although the vaccine regimen had a very modest effect (typical vaccines for other disease and conditions provide about 80-90 percent protection), it is the first HIV vaccine to demonstrate any ability to reduce the risk of HIV infection in people. Since the discovery of HIV, making a vaccine has been a major scientific goal of AIDS researchers. Until now, the field has been paved with setbacks and disappointments including two trials that were stopped in 2007 due to safety concerns. This new result reminds us that science is about finding answers and to do this, we must continue to conduct research.

HIV Vaccine Regimen Demonstrates Modest Preventive Effect in Thailand Clinical Study

By Kathy Stover, National Institute of Allergy and Infectious Disease, NIH

In an encouraging development, an investigational vaccine regimen has been shown to be well-tolerated and to have a modest effect in preventing HIV infection in a clinical trial involving more than 16,000 adult participants in Thailand. Following a final analysis of the trial data, the Surgeon General of the U.S. Army, the trial sponsor, announced today that the prime-boost investigational vaccine regimen was safe and 31 percent effective in preventing HIV infection.

“These new findings represent an important step forward in HIV vaccine research,” says Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, which provided major funding and other support for the study. “For the first time, an investigational HIV vaccine has demonstrated some ability to prevent HIV infection among vaccinated individuals. Additional research is needed to better understand how this vaccine regimen reduced the risk of HIV infection, but certainly this is an encouraging advance for the HIV vaccine field.”

To learn more, read the full press release and www.hivresearch.org for more information about the Thai Phase III HIV vaccine trial.