Health & Medicine - Posted by Dennis O'Shea-JHU on Friday, March 16, 2012 10:05 - 4 Comments
To kill latent HIV, lure it into an ambush
JOHNS HOPKINS (US) — AIDS experts have figured out a way to kill off the latent HIV that hides in infected T cells long after antiretroviral drugs suppress it to undetectable levels.
The strategy involves reactivating the HIV and coaxing it out of hiding, but only after boosting other immune system T cells and preparing them to ambush and eradicate the virus as it emerges.
“Our study results strongly suggest that a vaccination to boost the immune response immediately prior to reactivating latent virus may be essential for totally eradicating HIV infection,” says Robert Siliciano, professor at Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute investigator.
Straight from the Source
Siciliano was senior investigator of a team that tested the strategy on human immune system cells in the lab. Their report was published March 8 in the journal Immunity.
HIV has long been known to persist in a dormant, inactive state inside immune system T cells even long after potent antiretroviral drugs stop the virus from making copies of itself to infect other cells. But once drug treatment is stopped or interrupted, the latent virus quickly reactivates and HIV disease progresses. Researchers say it has proven all but impossible to wipe out the pockets of infection.
Siliciano, an infectious disease specialist who in 1995 first showed that these reservoirs of dormant virus survived, says the current need for HIV-infected patients to undergo lifelong drug treatment has raised concerns about the adverse effects of decades of therapy, the growing risk of drug resistance, and the rising cost of care.
The best hope for ultimately curing the disease is to force latent viruses to “turn back on”—making them “visible” to the immune system’s so-called cytolytic “killer” T cells—and then likely with the aid of drugs, to eliminate the infected cells from the body.
In his new study, Siliciano shows that infected T cells survived after latent virus was reactivated, and were only killed off when other immune system T cells were primed before reactivation.
In the report, Siliciano and colleagues describe how short pieces of HIV proteins were introduced to stimulate the anti-HIV T-cell response just before reactivation of the latent virus. Introduction of the incomplete viral proteins and the resultant immune system vaccination led to production of enough cytolytic T cells to attack and kill the latently infected cells.
Siliciano next plans to test different methods for boosting the immune response before latent virus reactivation and to compare their effectiveness in clearing all HIV-infected cells.
Currently, there are more than 34 million people in the world living with HIV, including an estimated 1,178,000 in the United States.
More news from Johns Hopkins University: http://releases.jhu.edu/