Why some primates, but not humans, can live with immunodeficiency viruses and not progre...(o not develop AIDS despite high levels o...)

Date:9/16/2008

o not develop AIDS despite high levels of ongoing SIV replication. Our studies sought to understand the basis for the very different responses to AIDS virus infections in different species," says Mark Feinberg, MD, PhD, the paper's senior author. Feinberg is a former investigator at the Emory Vaccine Center and the Yerkes Research Center and a professor of medicine at the Emory University School of Medicine. He currently serves as vice president of medical affairs and policy for vaccines and infectious diseases at Merck & Co., Inc.

The reasons are found in significant differences in immune signaling in a specific type of dendritic cells in AIDS-susceptible or resistant host species. Dendritic cells are part of the immune system that play a key role in alerting the body to the presence of invading viruses or bacteria, and in initiating immune responses that enable clearance of these infections. They detect the invaders using molecules called Toll-like receptors.

Feinberg's team found that in sooty mangabeys, dendritic cells produce much less interferon alpha--an alarm signal to the rest of the immune system--in response to SIV. As a result, the dendritic cells are not activated during the initial or chronic stages of SIV infection, and mangabeys fail to mount a significant immune response to the virus. In contrast to mangabeys, dendritic cells from humans and macaques that are susceptible to developing AIDS are readily activated by HIV and SIV.

The difference in whether or not dendritic cells become activated upon AIDS virus exposure in specific primate hosts appears to result from species-specific differences in patterns of Toll-like-receptor signaling. Because host immune responses are unable to clear AIDS virus infections, ongoing virus replication leads to unrelenting activation of the immune system in humans and macaques.

Unfortunately, rather than promoting clearance of the infection, chronic dendritic cell stimulation may
'/>"/>

Contact: Holly Korschun hkorsch@emory.edu 404-727-3990 Emory University Source:Eurekalert

0 GOOD

Page: 1 2 3 4
Related biology news :

1. Like humans, monkey see, monkey plan, monkey do
2. Features of replication suggest viruses have common themes, vulnerabilities
3. Gamma globulin effective in treating eye infections caused by adenoviruses
4. Discovery may help defang viruses
5. Prions and retroviruses -- an unholy alliance?
6. Study proposes new theory of how viruses may contribute to cancer
7. Iowa State researchers develop technology for early detection of viruses
8. Yellowstone viruses jump between hot pools
9. Great apes endangered by human viruses
10. The Uukuniemi virus helps to explain the infection mechanism of bunyaviruses
11. Viruses evolve to play by host rules, according to University of Pennsylvania researchers