The search for an HIV vaccine has taken a major step forward with the discovery of a potential Achilles heel of the virus that causes Aids. Two powerful antibodies that attack a vulnerable spot common to many strains of HIV have been identified, improving the prospects for a vaccine against a virus that affects an estimated 33 million people and kills over 2 million each year.The discovery is important because it highlights a potential way around HIVs defences against the human immune system, which have so far thwarted efforts to make a workable vaccine. The hope is that a vaccine that stimulates the production of these antibodies could remain effective against HIV even as the virus mutates. Scientists from the International Aids Vaccine Initiative (IAVI) are already examining the antibodies for clues to vaccine design. The new techniques used to discover the antibodies also promise further progress, as they should reveal other weaknesses in HIV that a vaccine might exploit.
The findings themselves are an exciting advance toward the goal of an effective Aids vaccine because now weve got a new, potentially better target on HIV to focus our efforts for vaccine design, said Wayne Koff, senior vice president of IAVI, which led the consortium behind the research. Having identified this one, were set up to find more, which should further accelerate global efforts in Aids vaccine development. Aids vaccine research has foundered to date because HIV mutates more quickly and easily than any other human pathogen yet discovered.
Vaccines work by teaching the immune system to recognise a particular germ and release antibodies to neutralise it, but HIVs shape-shifting nature allows it to evade these defences very rapidly. The newly discovered antibodies, called PG9 and PG16, are promising because they recognise parts of the virus that do not appear to change on a spike that HIV uses to infect cells. This suggests that they should be capable of attacking the virus in all its forms.
Dennis Burton, Professor of Immunology and Microbial Science at the Scripps Research Institute in La Jolla, California, who led the research team, said: These new antibodies, which are more potent than other antibodies described to date while maintaining great breadth, attach to a novel, and potentially more accessible site on HIV to facilitate vaccine design. So now we may have a better chance of designing a vaccine that will elicit such broadly neutralising antibodies, which we think are key to successful vaccine development.
Post published in: Analysis