Discovery of antibodies that kill more than 90% of HIV viruses gives new hope for vaccine

Jul 12 2010

"An effective vaccine against the AIDS virus may have moved one step closer to reality, researchers said Thursday," the Los Angeles Times reports. "Federal researchers have identified a pair of naturally occurring antibodies that are able to kill more than 90% of all strains of the AIDS virus, a finding they say could lead to the development of new treatments for HIV infections and to the production of the first successful vaccine against the virus" (Maugh, 7/9).

Wall Street Journal: "The HIV antibodies were discovered in the cells of a 60-year-old African-American gay man, known in the scientific literature as Donor 45, whose body made the antibodies naturally." The team of researchers, led by scientists at the National Institute of Allergy and Infectious Diseases (NIAID) reported their findings in two separate papers Thursday in an online issue of the journal Science, which comes just "10 days before the opening of the large International AIDS Conference in Vienna, where prevention science is expected to take center stage" (Schoofs, 7/9).

LiveMint.com: "AIDS vaccine development has proved to be harder than scientists' initial estimates, particularly because the virus evades the human immune system differently in different parts of the world. After scores of vaccine trials were unsuccessful, scientists had a glimmer of hope in 2009 when a late stage trial in Thailand showed that the vaccine could cut HIV infection by 31%. An early stage trial in Chennai in India in 2008 showed similar results, but arriving at a consensus on the right strategy for a vaccine isn't easy" (Singh, 7/9).

"The discovery of these exceptionally broadly neutralizing antibodies to HIV and the structural analysis that explains how they work are exciting advances," Anthony Fauci, director of NIAID said in a press release. "In addition, the technique the teams used to find the new antibodies represents a novel strategy that could be applied to vaccine design for many other infectious diseases," he added (7/8).

"The problem with fighting off HIV infection is that millions of variants of the AIDS virus now exist around the world because HIV constantly changes its surface appearance to avoid detection by the immune system," VOA News writes. "According to researchers at the [NIAID] Vaccine Research Center - part of the federally-funded National Institutes of Health [NIH], the two antibodies, called VRC01 and VRC02, interfere with HIV's ability to latch on to and cripple human T cells, the immune system's primary weapon against invaders" (Berman, 7/8).

How Scientists Made Discovery

Science News: For the first study, researchers "collected antibodies from the blood of HIV-infected people around the globe. They then tested these antibodies against nearly 200 strains of HIV in the lab to determine how many strains were susceptible to each antibody and how much antibody was needed to neutralize the virus."

The article continues, "VRC01 and its sister antibody VRC02 neutralize 91 percent of HIV strains, the team reports. A third antibody, VRC03, neutralized 57 percent. By comparison, an antibody discovered in the 1990s neutralized only about 40 percent of known HIV strains" (Seppa, 7/8).

Reuters: In the second study researchers "managed to freeze one of the antibodies in the process of attaching to and neutralizing the virus ... 'The antibodies attach to a virtually unchanging part of the virus, and this explains why they can neutralize such an extraordinary range of HIV strains,' Dr. John Mascola, [deputy director of the NIAID Vaccine Research Center] who worked on the study, said in a statement" (Fox, 7/8).

"The antibodies work by attaching themselves to a site on the virus that allows it to take over these disease-fighting cells - a site that has remained intact through countless mutations over the decades," the Canadian Press/CTV News adds, also quoting Mascola: "Antibodies like this are proof-of-concept that the human immune system can make very potent antibodies against HIV. … And that's very important information for helping us design a vaccine."

The article also includes a reaction to the findings from Alan Bernstein, executive director of the Global HIV Vaccine Enterprise, who describes how the studies support "the mood in the field has really turned around ... there's a sense that we're entering a new era in HIV vaccine research" (7/8).

Though Findings Are Promising, Scientists Say It Will Take Time To Develop Vaccine

HealthDay/Bloomberg Businessweek: Though enthusiastic about the findings, researchers struck a cautionary note: "The goal is to vaccinate individuals and have their own immune systems make an antibody like this," Mascola said. "To do that, we have to design a new vaccine, study it first in animal models, and then try it in small scale human studies, and see if it does what we expect it to do. That takes a quite a bit of time and effort" (Dotinga, 7/8).

Nature News examines some of the challenges associated with vaccine development: "A vaccine based on this work would have to stimulate the body to produce antibodies like VRC01. At present, researchers do not fully understand how this maturation process works, making it difficult to design a vaccine that would harness it appropriately" (Ledford, 7/8).

Bloomberg Businessweek: Though the antibodies themselves "can't be used in a vaccine as-is, the group [of researchers] has started work on a shot that would teach the immune system to make similar antibodies on its own" (Bennett, 7/8).

Researchers believe "these discoveries also may lead to development of a 'therapeutic vaccine' or immune-based therapy that helps train the innate immune system of an HIV-infected person to better control the virus without the use of drugs," Scientific American writes. "It may be possible to mass-produce these antibodies for passive administration as an adjunct or substitute for current small molecule drugs used to treat HIV. And if production costs can be reduced sufficiently there may be a role for them in topical microbicides as a preventative for HIV exposure" (Roehr, 7/8).

"While it may be years before the necessary human trials can be performed, this discovery is expected to accelerate ongoing efforts to find a HIV vaccine. It also picks up on what has become a fruitful vein for those researching in this field," Inter Press Service writes in a piece that looks ahead to the International AIDS Conference, AIDS 2010. "The organisers of the Vienna conference, which is expected to bring together 20,000 HIV/AIDS researchers, hope the gathering will help keep the spotlight on the importance of continued investment in HIV prevention, treatment, care and support, even in the face of the global economic crisis" (Berger, 7/8).

The Kaiser Family Foundation will provide webcasts of select session from AIDS 2010 starting with the Opening Session LIVE at 19:30 CEST/17:30 GMT/1:30 p.m. ET on Sunday, July 18.