While many researchers say an AIDS vaccine is distant - and some declare the prospect unrealistic - Pathology and Laboratory Medicine professor Carl June is pioneering a new gene therapy that could convert the HIV virus in a patient's body into a less harmful form.

While patients already can take "cocktails" of anti-retroviral drugs to manage the AIDS disease, such treatments are costly, ridden with unpleasant side-effects and ineffective in preventing the patient from passing on the virus.

June said he believes these downsides will be overcome by his treatment: a carrier of therapeutic genes that can be inserted into cells to bolster their immune response - possibly by weakening HIV when it attacks those cells.

Ideally, HIV victims treated with June's therapy would only be able to pass on a less virulent form of the virus, resulting in an overall "vaccine effect."

Laboratory and small clinical tests over the past five years have shown that this therapy suppresses HIV from spreading within the body.

June said the treatment "might be a way to vaccinate patients by giving them a virus that's less destructive, so the patient's own immune system could control it, and they wouldn't have to take pills for the rest of their life."

Paula Cannon, who teaches at the University of Southern California and works to develop anti-HIV gene-therapy strategies for children at the Children's Hospital Los Angeles, said that "what I find exciting about gene therapy is it has the potential to be a one-shot solution."

Still, according to Penn Hematology and Oncology professor James Hoxie, only the real vaccine can end the pandemic.

"There's no question treatment is important, but to be infected with HIV is to be infected for life. Nothing has changed that," he said. "You can't turn your back on the need to do everything you can to prevent infection."

About 33 million people worldwide are infected with HIV, according to UNAIDS.

But hope for a vaccine is "almost wishful thinking," Cannon said.

"Everything that nature's told us about the natural infection seems to say that we cannot make a vaccine."

She also said gene therapy has long been notoriously unpopular among medical researchers.

"Gene therapy approaches are kind of hanging off the edge of the cliff by their fingertips" because so few companies are willing to fund the research, she said.

According to Phalguni Gupta, professor of infectious diseases and microbiology at the University of Pittsburgh, few HIV researchers are pursuing gene therapy because it is difficult to alter the genes of the billions of cells affected by a virus.

Gene therapy is "difficult to do, difficult to deliver," he said. "When you put the cells in the body, the body's first reaction is to get rid of them," usually after just a few days.

But the nine patients who received June's treatment displayed what appeared to be "very promising" reactions that lasted even when the therapy was temporarily discontinued for several days.

It will likely be at least five years before June's therapy is approved by the Federal Drug Administration, assuming it proves successful in further clinical trials.