Researchers have made a surprising discovery in the search for an AIDS vaccine that suggests the answer lies within the feline virus, according to a news release.

Scientists from the University of Florida (UF) and the University of California, San Francisco (UCSF) found blood samples from HIV-infected humans showed an immune response against a cat AIDS virus protein.

The study's finding, published in the current issue of the Journal of Virology, further suggests feline AIDS could help scientists develop a vaccine for the human virus.

"One major reason why there has been no successful HIV vaccine to date is that we do not know which parts of HIV to combine to produce the most effective vaccine," said co-author Janet Yamamoto, a professor of retroviral immunology at the UF College of Veterinary Medicine.

The researchers' work is based largely on the role T cell peptides play in recognizing infected cells and attacking them. The vaccine would activate an immune response in T cells against the HIV virus in infected people. Yamamoto said not all HIV peptides act as vaccine components.

"In humans, some peptides stimulate immune responses, which either enhance HIV infection or have no effect at all, while others may have anti-HIV activities that are lost when the virus changes or mutates to avoid such immunity," she said. "So, we are looking for those viral peptides in the cat AIDS virus that can induce anti-HIV T-cell activities and do not mutate."

UCSF medicine professor and study co-author Dr. Jay A. Levy reassured patients the feline and human virus simply resemble one another, nothing more.

"We want to stress that our findings do not mean that the feline AIDS virus infects humans, but rather that the cat virus resembles the human virus sufficiently so that this cross-reaction can be observed," he said.

Yamamoto said there is not a current T-cell-based vaccine designed to prevent viral diseases. She said the team's research aims to use the body's immune system to fight the virus.

"So we are now employing an immune system approach that has not been typically utilized to make a vaccine," she said. "The possible use of the cat virus for this vaccine is unique."

University of Pittsburgh microbiology and molecular genetics professor Michael Murphy-Cobb said he has known Yamamoto since she discovered the feline AIDS virus.

Said Murphy-Cobb, "Dr. Yamamoto has identified the immunological Achilles' heel of HIV."