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HIV Vaccine Advances Made Ahead of Global Conference

Matthew O. Berger

WASHINGTON, Jul 8 2010 (IPS) - In 1984, then-U.S. Secretary of Health and Human Services Margaret Heckler famously declared, “We hope to have such a vaccine ready for testing in approximately two years.” The vaccine in question would prevent AIDS and the goal Heckler set has been missed by over 26 years.

During that time, around 25 million people have died from the disease and the search for a vaccine continues.

But two studies released Thursday in the journal Science give some hope to those that have worked so long on this cause. In them, researchers disclose the discovery of two antibodies – which identify and fight off viruses in the blood stream – that can stop 90 percent of known HIV strains from infecting human cells in the laboratory.

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.

One of the primary difficulties with developing a vaccine for HIV – and the primary obstacle overlooked by Heckler and many other scientists in the mid-1980s – is that HIV is a diverse and ever-changing virus. The virus continually changes the proteins that coat its surface, such that it can continually evade detection by antibodies and meaning a huge number of HIV strains currently exist in the world.

To be able to design a vaccine that can keep up with the continuous transformation of the virus and be globally effective, then, is much more than a two-year process.

But in recent years, scientists have found several antibodies that seem to have an effect on at least a majority of HIV strains. The Science study identifies two such antibodies.

First, the scientists, led by a team from the National Institute of Allergy and Infectious Diseases (NIAID), identified areas on the surface of HIV that remain the same across all strains. One of areas, called the CD4 binding site, helps the HIV attach to and infect the human immune system. But they found that two antibodies, VRC01 and VRC02, can block infection by attaching to that binding site and blocking the HIV from attaching to immune system cells.

“The antibodies attach to a virtually unchanging part of the virus, and this explains why they can neutralise such an extraordinary range of HIV strains,” said John Mascola, a co-author of one of the studies and the deputy director of the NIAID’s Vaccine Research Center.

They also have determined how the latter antibody works and where precisely it attaches to the virus, thus enabling them to begin to lay the groundwork for a vaccine that might aid the immune system in making antibodies to prevent infection by 90 percent of HIV strains.

“The discoveries we have made may overcome the limitations that have long stymied antibody-based HIV vaccine design,” says Peter Kwong, a researcher at NIAID and a co-author of one of the Science studies.

Other researchers have taken a different route than building antibodies. A study released in the journal Nature Biotechnology on Friday disclosed how researchers at the University of Southern California engineered human stem cells so that the gene that allows HIV to enter the cells was disabled, as it is in a small percentage of people. Mice in which these engineered human cells were multiplied and which were then infected with HIV were protected from the virus.

This gene therapy solution, like the antibody-based vaccine, is still a long way from being successfully used in people, but researchers hope the progress that is being made means their work will continue to be funded, even in a tough economic climate.

That gap between scientists and the governments that fund HIV/AIDS research will be a central issue addressed by the International AIDS Conference, which begins July 18 in Vienna.

Looking ahead to this conference, Science contains a special section with additional studies on the prevalence and impact of HIV/AIDS. One article says that fewer than one in eight of those currently living with HIV have access to antiretroviral therapy and that many lack access to preventive measures. In another report, researchers and several NGO representatives point out that U.N. members agreed in 2006 to make comprehensive programs for HIV prevention, treatment and care universally available by the year 2010.

While “this commitment has inspired national and international responses to achieve impressive results”, they write, the goal of universal access has not been met.

“If governments globally don’t do more in terms of the quality and quantity of care for people with HIV, this will result in dire human and economic costs in the short and long term,” said co-author Julio Montaner, director of the British Columbia Centre for Excellence in HIV/AIDS, president of the International AIDS Society.

While continued work on vaccines and preventions may bode well for the effort to end the HIV pandemic, then, there are still many opportunities to do more. In the meantime, another 2.7 million people will continue contract the disease each year.

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.

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