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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.

鈥淥ne 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,鈥� said , Ph.D., a professor of retroviral immunology at the and the study鈥檚 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鈥檚 T cells to recognize viral peptides on infected cells and attack them. However, not all HIV peptides can work as vaccine components, Yamamoto said.

鈥淚n 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,鈥� she said. 鈥淪o, we are looking for those viral peptides in the cat AIDS virus that can induce anti-HIV T-cell activities and do not mutate.鈥�

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 said.

鈥淪urprisingly, we have found that certain peptides of the feline AIDS virus can work exceptionally well at producing human T cells that fight against HIV,鈥� she said.

The researchers isolated T cells from HIV-positive individuals and incubated these cells with different peptides that are crucial for survival of both human and feline AIDS viruses. They then compared the reactions they got with feline immunodeficiency virus (FIV) peptides to what they found using HIV-1 peptides.

鈥淲e found that one particular peptide region on FIV activated the patients鈥� T cells to kill the HIV,鈥� Yamamoto said

This feline viral region identified by human cells appears to be evolutionarily conserved 鈥� it is present in multiple AIDS-like viruses across animal species, she added.

鈥淭hat means it must be a region so essential that it cannot mutate for the survival of the virus,鈥� she said.

Yamamoto and her team believe that the feline AIDS virus can be used to identify regions of the human AIDS virus that might be more effectively used in a vaccine-development strategy for HIV.

鈥淲e 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,鈥� said study collaborator Jay A. Levy, M.D., a professor of medicine at UCSF.

To date, a T-cell-based vaccine has not been used to prevent any viral diseases, Yamamoto said.

鈥淪o we are now employing an immune system approach that has not been typically utilized to make a vaccine,鈥� she said. 鈥淭he possible use of the cat virus for this vaccine is unique.鈥�

Michael Murphey-Corb, Ph.D., a professor in the department of microbiology and molecular genetics at the University of Pittsburgh, has known Yamamoto since she discovered the feline AIDS virus.

鈥淒r. Yamamoto has identified the immunological Achilles鈥� heel of HIV,鈥� Murphey-Corb said.

Levy, along with Mobeen Rathore, M.D., director of the , and the University of South Florida in Tampa provided the blood from HIV-infected subjects. Other collaborators include the , the , and LifeSouth Community Blood Centers of Gainesville.

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Research reported on in this news release was supported by the National Institutes of 网红黑料 under RO1AI65276, RO1AI30904 and RR029890. This content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of 网红黑料.