Human World

Gary Nabel on recent breakthrough in AIDS vaccine research

Researchers are closer than ever to finding a vaccine that prevents AIDS. That’s what Gary Nabel told us. He’s director of the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases in Maryland. He said the AIDS virus, also known as HIV, has been so difficult to stop because it mutates at a dizzying rate.

Gary Nabel : There are millions and millions of strains of the AIDS virus. For example, if you looked at the number of viruses in a single person infected with the HIV virus, there are more viruses in that individual than would circulate in an influenza outbreak in the entire world in one year.

He said most people infected with the AIDS virus mount an immune defense – that is, produce antibodies – that knock out only a few strains of the AIDS virus. But, in July 2010, Dr. Nabel reported in the journal Science that his team had identified several rare, broad-acting antibodies, the most powerful of which could attack or neutralize 90% of strains. These antibodies were found in the blood of a patient living with AIDS, known as Donor 45.

Gary Nabel Knowing that a human is capable of making those antibodies really gives us some optimism that we may be able to elicit those antibodies by vaccination.

He explained that powerful antibodies can serve as a kind of template to build a vaccine around. Nabel estimated that a publicly available AIDS vaccine is still at least 10 years away. He expressed cautious optimism.

Gary Nabel: For an AIDS vaccine for many years we’ve been driving around in the dark without a map, and I now I think we’ve got some very sophisticated tools that give us direction.

Nabel added that an increased knowledge of the structure of the AIDS virus itself – especially its weak points – are also helping scientists build an AIDS vaccine.

Gary Nabel: The AIDS pandemic is one that’s affected more than 60 million people, more than 30 million people have died. And I think the challenge for us is really to harness the best of our science, the best of our medicine, the best of our technology to really find a way, whether it be through vaccination, or a combination of other prevention strategies, to try to turn the tide on this.

He described more specifically how he’ll be using the antibodies in vaccine research.

Gary Nabel: We can use it to create proteins, what I might call “designer” proteins, where we deliberately change the shape of those proteins where they interact very specifically with the HIV neutralizing antibodies that we have cloned. And so that’s a way of essentially trying to teach the immune system to try to generate those antibody responses on their own.

He added that this same method might be used to create vaccines for other viruses, and even autoimmune diseases. He also explained why it takes so long to get from the ID of antibodies to the creation of a vaccine ready for the public.

Gary Nabel: Even if we were able in the coming weeks – which won’t happen – to identify a vaccine candidate that we really felt could elicit this response, by the time you would take that forward into clinical production, and to do trials would take a couple of years, just to get started, by the time you could get an efficacy trial, that might take another five years. Really, if we had one in less than 10 years, that would be a surprise to me right now.

July 20, 2010
Human World

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