Gene Therapy Proving Successful in Fight Against AIDS

For decades, researchers and scientists have fought valiantly searching for a cure and a vaccine for the AIDS virus. Animal and human trials alike have been performed all across the globe in the hopes that a cure can be discovered to end the epidemic once and for all. To date, there have been many unsuccessful attempts at a vaccine that would urge the human immune system to fight the virus. Now, in an attempt to outsmart the virus, scientists are testing gene therapy that has proven successful in monkey trials and hopefully will prove just as successful in humans.

A research team headed by Dr. Philip Johnson (from Philadelphia’s Children’s Hospital) is conducting trials where a gene is inserted into a muscle that causes the body to actively produce HIV antibodies. Trials began in mice and when those proved successful, they turned to monkey trials which also were successful. Johnson was quick to point out, however, that while these trials worked well, there is much work to be done before they can begin testing on human patients. Dr. Beatrice Hahn, one of the researchers on Johnson’s team, is hopeful about the future of their project. Hahn states, “It basically shows there is light at the end of the tunnel. It shows thinking outside the box is a good idea and can yield results, and we need perhaps more of these nonconventional approaches.”

Most of the research conducted into creating an AIDS vaccine have centered on helping a human’s immune system to produce those antibodies that would keep the virus at bay. These are the same research models that helped in creating vaccines for both smallpox and measles. However, this type of model has not been successful with AIDS. This is why Johnson and his team decided to go a different route. Johnson says, “We used a leapfrog strategy, bypassing the natural immune system response that was the target of all previous HIV and SIV vaccine candidates. Some years ago I came to the conclusion that HIV was different from other viruses for which we were trying to develop vaccines and we and might not ever be able to use traditional approaches.”

In research that spanned a decade, Johnson and his committed team worked on creating immunoadhesins. Essentially, these are proteins similar to antibodies which would attach themselves to the virus and prevent it from infecting other cells. Once those immunoadhesins were created, they needed to devise a way to get them into the cells. They utilized an adeno-associated virus which they injected into the muscles. This virus also held the immunoadhesins’ DNA. Once this was performed, those muscled started creating the proteins that would keep the cells protected.

Once the trials were successful with mice, they decided to try monkey trials since SIV (the simian version of HIV) and HIV are very similar. They had 15 monkeys total, nine of them treated/immunized and six of them not. Of those monkeys that were immunized, none developed AIDS. A year after the trials, the immunized monkeys were tested and still showed high levels of those protective antibodies. Of the monkeys that were not immunized, all were infected and four of them died due to the infection. With these successes, the research team would need to push forward with human trials which may happen as early as a few years.