|HIV particle infecting a human T cell--Courtesy of National Institute of Allergy and Infectious Diseases (NIAID)|
Despite many attempts, a vaccine for HIV/AIDS has eluded scientists for years. The structure and mutable nature of HIV has made the task difficult, but in the urgent pursuit to find a protective treatment, Oregon Health & Science University's Vaccine and Gene Therapy Institute is making major inroads.
Testing their approach in monkeys, researchers found that their vaccine completely cleared the virus from about half of the animals with the HIV-like virus simian immunodeficiency virus (SIV).
About 50% of monkeys given highly pathogenic SIV after being vaccinated became infected with SIV but over time eliminated all traces of SIV from the body. In effect, the hunters of the body were provided with a much better targeting system and better weapons to help them find and destroy an elusive enemy.
"To date, HIV infection has only been cured in a very small number of highly-publicized but unusual clinical cases in which HIV-infected individuals were treated with anti-viral medicines very early after the onset of infection or received a stem cell transplant to combat cancer," said researcher Dr. Louis Picker, associate director of the OHSU Vaccine and Gene Therapy Institute, in a university news release. "This latest research suggests that certain immune responses elicited by a new vaccine may also have the ability to completely remove HIV from the body."
Detailed in the journal Nature, scientists engineered the HIV vaccine using a common and usually harmless virus, cytomegalovirus (CMV), which is carried by a large percentage of the population. When the CMV was exposed to SIV, it spurred a T-cell response that attacked the SIV, beefing up the monkeys' defenses to fight the HIV-like virus. In other words, the vaccine gives the monkeys' immune system better tools to destroy the infection. Over time, the SIV was completely cleared from half the monkeys.
SIV is 100 times more deadly than HIV, so it's a noteworthy feat that the vaccine cleared the virus in even half the animals. The OHSU researchers are now working on figuring out why some monkeys responded to the vaccine while others did not. Picker and his team hope to soon test the vaccine in humans.
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