According to the recently released Nature Magazine article, “Gene Therapy Can Protect Against HIV” a team of biologists at California Institute of Technology in Pasadena, California have developed a new approach to HIV prevention.
This new approach called Vectored ImmunoProphylaxis or VIP uses gene therapy an approach most commonly recognized for curing genetic diseases not necessarily the prevention.
“VIP has a similar effect to a vaccine, but without ever calling on the immune system to do any of the work,” Alejandro Balazs, lead author of the study, said.
“Normally, you put an antigen or killed bacteria or something into the body, and the immune system figures out how to make an antibody against it. We’ve taken that whole part out of the equation,” he said.
This new approach builds on earlier work by scientists at the Children’s Hospital of Philadelphia in Pennsylvania, who in 2009 first described the effectiveness of this technique in preventing the transmission of simian immunodeficiency virus in monkeys.
More than 2 million adults are infected with HIV every year and still even close to 30 years after the virus was first identified in the 1980s, researchers still haven’t found a cure or a way to prevent the initial infection. Researchers have had a tough time finding a molecule that can induce even moderately broad responses against the virus in all its different mutations. While gene therapy might not be the first method of prevention most think of, it could be the much-needed alternative the world has been waiting for.
As taken from the Nature article, “The researchers used specialized mice carrying human immune cells that are able to grow HIV and utilized an adeno-associated virus (AAV), a small, harmless virus that has been useful in gene-therapy trials, as a carrier to deliver genes that are able to specify antibody production. The AAV was injected into the leg muscle of mice, and the muscle cells then put broadly neutralizing antibodies into the animals’ circulatory systems. Researchers found that mice treated with just a single AAV injection appeared to have 100 percent protection against HIV.”
It was also found that after just a single AAV injection, the mice produced high concentrations of these antibodies for the rest of their lives, as shown by intermittent sampling of their blood.
Gene therapy allows for the permanent insertion of the antibody DNA into the genome, there isn’t currently a way to “turn it off” if someone has an immune reaction against the antibodies. These side effects won’t be known until the method is tested in people, something that David Baltimore, a virologist and HIV researcher at Caltech aims to do in the next few years.
As Baltimore says, “This is something way out of the ordinary, and it’s perfectly reasonable to say that there’s no reason to do it if there’s an alternative, but if there’s no alternative – and that’s where we’re at today – then we should be thinking of new ways to protect people.”