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 .

Dr. Anthony S. Fauci's Statement on the CAPRISA 004 Microbicide Study

Dr. Anthony Fauci

On July 19, 2010, Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, National Institutes of Health, released a statement to acknowledge the results from the CAPRISA 004 Microbicide Study. To read the entire statement, visit the NIAID website.

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Today we congratulate the Centre for the AIDS Programme of Research in South Africa (CAPRISA) and the people of South Africa on the positive findings from the CAPRISA 004 microbicide study , which marks a significant milestone both for the microbicide research field and HIV prevention as a whole.

For years, antiretroviral medicines have been effectively used to treat HIV infection. Through the successful conduct of the CAPRISA 004 study, we now have proof that an antiretroviral drug, in this case tenofovir, can be formulated into a vaginal gel that can protect women against HIV infection. Given that women make up the majority of new HIV infections throughout the world this finding is an important step toward empowering an at-risk population with a safe and effective HIV prevention tool.

The CAPRISA 004 study is an exciting scientific achievement that moves us one step forward to gaining another effective tool to prevent HIV infection. However, because no one approach will be appropriate or acceptable to all, we must continue to pursue a range of HIV prevention modalities, including microbicides, PrEP, and vaccines, as we simultaneously pursue scientific strategies designed to bring us closer to finding a cure for HIV/AIDS.”

Read complete statement.

Future Directions for NIAID’s HIV Vaccine Clinical Research

By Carl W. Dieffenbach, Ph.D., Director of NIAID’s Division of AIDS, and Margaret I. Johnston, Ph.D., Director of the Vaccine Research Program in NIAID’s Division of AIDS

Carl W. Dieffenbach, PhD

Margaret I. Johnston, PhD

The development of a safe and effective preventive vaccine for HIV remains one of NIAID’s highest priorities. As we look to the future, we are also seeking to expand the capability of our HIV vaccine clinical research infrastructure to contribute to the development of vaccines for other infectious diseases of public health significance that impact people who are infected with HIV and those who are at risk for HIV infection.

HIV vaccine development has presented significant challenges for the scientific community. However, in late 2009, we obtained the first clinical evidence that a safe and effective HIV vaccine may indeed be possible. The RV144 Thai trial showed that an experimental “prime-boost” vaccine regimen was safe and 31 percent effective in preventing HIV infection. This information brought renewed hope and optimism to researchers and the HIV/AIDS community. Most recently, the identification by NIAID-led scientists of two new broadly neutralizing human antibodies that can prevent more than 90 percent of known HIV strains from infecting human cells will certainly help to advance HIV vaccine design. As we chart a path forward, we must keep our eye on the goal of developing a safe and effective vaccine that prevents HIV acquisition. To achieve this goal, we are following a two-pronged approach for an HIV vaccine.

The first approach grew out of the 2008 NIAID HIV vaccine summit and consists of a strengthened commitment to basic vaccine discovery for HIV. For example, investigators are actively evaluating the earliest steps during HIV infection and how a vaccine may influence the course of infection. Studies in non-human primates are addressing questions that cannot be addressed in humans. This has resulted in a proliferation of new ideas and concepts to pursue, and we must continue to encourage “out of the box” thinking and approaches to HIV prevention. As these lines of thinking and research progress, we hope that some ideas will mature into novel vaccine concepts worthy of further evaluation. Clearly, an important component of the research endeavor is the eventual evaluation of the most promising new concepts for safety and activity in humans, which includes testing candidate HIV vaccines with acquisition of infection as a clinical trial endpoint.

Looking Ahead: NIAID’s Future HIV/AIDS Therapeutics Priorities

By Carl W. Dieffenbach, Ph.D., Director of NIAID's Division of AIDS

Since the 1980s when the HIV/AIDS epidemic was first recognized, NIAID-supported clinical research has helped to save millions of lives and played a key role in defining the standard of care for treating HIV infection. This blog post describes what we are seeking for the next wave of HIV/AIDS therapeutic approaches. Specifically, we have identified the following three research priorities: 1) finding a cure for HIV-infected individuals; 2) developing therapeutic strategies for preventing and treating tuberculosis (TB) and hepatitis C in HIV-infected individuals and individuals at high risk for co- infection; and 3) addressing the long-term consequences of treatment of HIV infection.