TORONTO – A novel vaccine that stimulates the immune system to seek out and destroy HIV is showing promise for people infected with the virus that causes AIDS.
Reporting here at the XVI International AIDS Conference, Pittsburgh researchers say the experimental HIV vaccine uses a souped-up version of a patient’s own cells to battle the virus.
Used in combination with antiviral drugs, the vaccine will pack a one-two punch against HIV, says researcher Charles R. Rinaldo Jr., PhD, chairman of the department of infectious diseases and microbiology at the University of Pittsburgh's Graduate School of Public Health.
“While HIV drugs can keep the virus in check, they do not wipe it out,” Rinaldo says. “As soon as a person goes off the drugs, the virus comes roaring back.” As a result, HIV-positive people often have to take anti-AIDS medications for life.
“Our hope is to boost the immune system to go after the reservoir of virus that remains in such people. Then they wouldn’t have to be on lifelong therapy or could at least take fewer drugs, with less cost and less toxicity,” he tells WebMD.
A trial of the custom-made vaccine is scheduled to begin later this year, pending approval by the FDA.
How It Works
Unlike flu and most other vaccines, the HIV vaccine is not intended to be given to healthy people to prevent disease. Rather, it is being developed to help HIV-positive people bolster their immune system to better fight the virus.
To do that, the vaccine is loaded up with powered-up dendritic cells, which have been galvanized to rally killer T cells to fight the virus unique to an individual.
The researchers start with an HIV-infected person’s own blood, from which they obtain dendritic cells -- potent immune-system-stimulating cells in the body.
Then, they load the dendritic cells up with chemicals that enhance their ability to process HIV – they chew it up into small pieces, if you will.
The manipulated dendritic cells can now more efficiently turn on the immune system’s killer T cells to seek and destroy HIV-infected cells, Rinaldo says.
In test tube studies, “we got three to 10 times better killing of HIV,” he says.
Stefano Vella, MD, an AIDS specialist at the Istituto Superiore di Sanita in Rome, says the strategy shows promise.
“While there is no proof yet that the vaccine stops disease progression, it’s a natural approach that offers great hope,” he tells WebMD.
That said, the cost might be prohibitively expensive for many people, as each vaccine has to be custom-made and multiple treatments may be needed, Vella adds.
By Charlene Laino, reviewed by Louise Chang, MD
SOURCES: XVI International AIDS Conference, Toronto, Aug. 13-18, 2006. Charles R. Rinaldo Jr., PhD, chairman, department of infectious diseases and microbiology, University of Pittsburgh's Graduate School of Public Health
Stefano Vella, MD, Istituto Superiore di Sanita, Rome.
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