Scientists Uncover Antibodies That Could Lead to AIDS Vaccine
After having studied one person's astonishing immune response to AIDS, American researchers have observed a series of mutations which led to an antibody that can defeat several strains of H.I.V. While the development of a vaccine is still far to come, the research shows a promising hope for the future.
There are 34 million people who are H.I.V. positive worldwide, 2.5 million who contract the virus every year, 50,000 of whom live in the United States.
"The beauty of this is that it's a big clue as to the sequential steps the virus and the antibody take as they evolve," said Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, the organization which financed the research.
Scientists have thus far have failed to create an AIDS vaccine due to the rapid daily mutation in H.I.V. However, the study led by scientists at Duke University analyzed sequential blood samples from an infected African man which could be the key to protecting against many strains of H.I.V. Several other researchers were also part of the study, including scientists from the University of Pennsylvania, Stanford and Colombia. The findings were published online in the journal Nature.
After analyzing the H.I.V positive African man from shortly after he was infected until about two years later, scientists discovered that he started to produce "broadly neutralizing antibodies," which were able to battle about 55 percent of all H.I.V. strains. Antibodies are proteins that serve to neutralize virus particles by grabbing onto all the surface receptors they use to attach to cells.
While about 20 percent of all H.I.V. carriers eventually produce broadly neutralizing antibodies, this does not happen until the patient has been infected between two and four years. By this time, the virus has mutated so much that no matter how powerful the antibodies are, they cannot fight the virus.
Over the course of several years, scientists have been isolating broadly neutralizing antibodies and have found more than a dozen. If these antibodies could be cloned on a mass scale to provide enough variants to match all known H.I.V. strains, a vaccine similar to an immunoglobulin shot could be given to newly infected patients.
Based on scientists research this treatment would be very expensive and would have to be provided to patients for life. Meanwhile more affordable antiretroviral drugs cost a fraction of the price and serve the same purpose of preventing the H.I.V. virus from replicating.
In contrast, if a vaccine were developed for a healthy patient that would induce his white blood cells to produce a wide variety of antibodies for the virus, it could potentially defeat any infection the patient later contracted.
Producing a vaccine for the virus would mean administering many shots month after month due to the cells undergoing up to 100 mutations before they produce broadly neutralizing antibodies, according to Dr. Fauci. It is still unknown whether the vaccine is possible or even financially sound.
Other experts reacted cautiously to the research, criticizing it as first-rate work but hedging on its practical implications, according to the New York Times.
Scientist Dr. Joseph McCune III, from the University of California, San Francisco referred to the study as "clarifying science, with a lot of data I hadn't seen before," and questioned whether one person's immune response to the virus could be helpful to others.
"Eighty percent of all patients don't create broadly neutralizing antibodies," he stated. "What do we do for them? Do we know how protective this strategy is against new infections? And would we have to tailor-make batches of vaccine for people with different backgrounds?"
H.I.V. specialist, Dr. Louis J. Picker of Oregon Health & Science University also compared the work to "a road map to vaccine development, yes - but it's like one of those maps of the world from the year 1400. We still don't know how to turn this into a vaccine."