Innovative work continues in effort to find HIV vaccine

“Almost a year ago the results of the Thai RV 144 trial were announced, providing the first evidence that a vaccine is able to prevent HIV acquisition,” said Alan Bernstein of the Global HIV Vaccine Enterprise. “That level of protection, 31 percent, is not enough to create a product, but it is a very important proof of concept.”

The Enterprise is based in New York City and works to coordinate the global efforts to develop an effective HIV vaccine. It supported Emory University as it hosted the AIDS Vaccine 2010 conference in October. Over 1,000 researchers from 47 countries attended the conference to share research and look for possible points of collaborations.

Dozens of researchers from across the world presented their findings or concepts that they were exploring. Atlanta-based Dr. Harriet Robinson of GeoVax is working with Dr. Rama Amara and others at Emory University on a vaccine that has the possibility of preventing the infection and then controlling viral loads in those who are already positive.

“We feel that we had sterilizing protection, and the reason we feel we had sterilizing protection is because first we could not detect the virus and second we could not detect immune responses,” Robinson said of her research.

Her vaccine is similar to the Thai vaccine, and some like Dr. Steven Self of the HIV Trials Network believe that a cure may be found in a combination of vaccines with a Pre-exposure Prophylaxis, or PrEP, that could result in a much higher level of protection than either could give on its own.

“Since RV 144 offers 31 percent efficacy and PrEP offers 40 percent efficacy we could see a result anywhere between 40 to 70 percent,” Self said. “But the idea of synergy is that by combining these two components you would end up with a final product that could be more effective than the sum of the two components.”

High-risk projects underway

José Esparza is the HIV vaccine senior adviser to the Bill & Melinda Gates Foundation. The multi-billion dollar fund works on finding solutions to global problems such as HIV, where it has donated almost $300 million.

“We focus in four areas. The first one is priming the idea pipeline with small investments in highly innovative, high risk, high reward discovery projects. These are new ideas that would not be supported by any conventional foundation, probably would not pass peer review but are sufficiently innovative for us in the foundation to provide small funding,” Esparza said. “We don’t want to add more money to what everyone else is already funding — we want to support those new and innovative ideas that no one is supporting that may lead to new HIV vaccines.”

New researchers are looking at areas that may have been overlooked by their established colleagues. Dr. Hendrik Streeck, a researcher at the Ragon Institute, is researching T-Cell stimulation, a potentially risky idea that he thinks could be beneficial.

“If you induce the CD4 cells to target HIV you basically generate more target cells for the virus, but it has never been tried,” Streeck said. “I really like this idea to try and figure out if their integral functions are critical to maintain control, and I think at the very least it should be tried.”

Dr. Peter Kwong and Dr. John Mascola of the Vaccine Research Center in Bethesda, Md., have published research this year of a broad-binding antibody that can effectively stop HIV-1.

“The virus has to enter the cell and attach to certain receptors. Binding those receptors forces part of the cell to be the same, and that’s where this antibody attacks the virus, in the functional related part that the virus has to enter,” Kwong said.

Mascola said that finding a vaccine is mostly likely going to part of an overall cure to AIDS, and said that even his approach wasn’t likely to have therapeutic value to those already positive by itself.

“The potential difficulty of using a single agent of any kind to treat HIV infection is, as you know well, AZT by itself it wasn’t very effective, it was only when there were triple drugs and the virus would have to adapt to not just one drug but two others as well,” he said. “It would most likely be considered in the realm of supplementing potent anti-viral drugs.”


Top photo: Dr. Hendrik Streeck (right), a researcher at the Ragon Institute, is researching T-Cell stimulation as a way to stem HIV infection. (by Matt Schafer)