April 5, 2013
HIV Vaccine May Come From Our Evolving Antibodies
Brett Smith for redOrbit.com - Your Universe Online
When HIV enters the human body, it begins an arms race with the immune system which is constantly attempting to develop new ways to destroy the invader. Unfortunately, the body is at some point overwhelmed by a multitude of HIV mutations before the immune system is able to develop a superweapon against the virus.However, some immune systems do develop a superweapon called "broadly neutralizing antibodies” a few years after the initial infection, and some doctors believe that the key to defeating the virus could be the preemptive creation of these antibodies.
In a new study published in the journal Nature, scientists closely monitored the evolution of both HIV and the body´s immune response to it in an African man starting just weeks after his initial infection. About two years after the infection, the scientists watched as the patient´s body began producing highly effective, broadly neutralizing antibodies.
Antibodies are Y-shaped proteins that attack a virus by attaching to the surface receptors that it uses to bind to cells. The broadly neutralizing antibodies in the study effectively defused about 55 percent of all known HIV strains.
“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,” Dr. Anthony S. Fauci, director of the study-financing National Institute of Allergy and Infectious Diseases, told the New York Times.
Scientists have identified more than a dozen broadly neutralizing antibodies over the past few years, and many expect that a combination of these powerful disease fighters may eventually be able to take down all known strains of HIV.
Such and antibody cocktail could be given to newly infected patients and would function much like an immune globulin shot, which has been used to treat diseases like hepatitis. However, doctors say that this type of treatment would be very expensive and would have to be taken for the life of the patient.
Another option would be to spur a person´s immune system to create broadly neutralizing antibodies that would then lie in wait for a potential infection.
“Our hope is that a vaccine based on the series of HIV variants that evolved within this subject, that were together capable of stimulating this potent broad antibody response in his natural infection, may enable triggering similar protective antibody responses in vaccines,” said co-author Bette Korber, from the Los Alamos Laboratory and Sante Fe Institute in New Mexico.
According to Fauci, the naturally occurring production of broadly neutralizing antibodies occurs only after the cells that produce them have gone through about 100 mutations. An effective vaccine would require a series of monthly shots that would accelerate the pace of these mutations.
Such a treatment is purely theoretical at this point and reaction to the plan remains critical yet optimistic.
Dr. Louis J. Picker, from the Oregon Health & Science University, described the study as “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,” the New York Times reported.