Blood from HIV-infected human subjects shows an immune response against a cat AIDS virus protein, a surprise finding that could help scientists find a way to develop a human AIDS vaccine, report University of Florida and University of California, San Francisco researchers.
Their findings appear in the October issue of the Journal of Virology. This discovery supports further exploration of a human AIDS vaccine derived from regions of the feline AIDS 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,” says Janet Yamamoto, a professor of retroviral immunology at the UF College of Veterinary Medicine and the study’s corresponding author.
The researchers are working on a T-cell-based HIV vaccine that activates an immune response in T-cells from HIV-positive individuals against the feline AIDS virus. T-cell peptides are small pieces of protein that can prompt the body’s T-cells to recognize viral peptides on infected cells and attack them. However, not all HIV peptides can work as vaccine components, Yamamoto says.
“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 says. “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.”
In previous studies, scientists have combined various whole HIV proteins as vaccine components, but none have worked well enough to be used as a commercial vaccine, Yamamoto says.
“Surprisingly, we have found that certain peptides of the feline AIDS virus can work exceptionally well at producing human T-cells that fight against HIV,” she says.