US researchers find two chemicals to fight HIV
Two chemical compounds may help the immune systems of HIV-infected people fight the disease without invasive gene therapy, US scientists reported Saturday.
The new research, presented at the 2005 Palm Springs Symposium on HIV/AIDS, was conducted by researchers at the University of California, Los Angeles(UCLA) AIDS Institute. It demonstrates that the new chemicals activate telomerase, a protein that boosts immune cells' ability to divide, enabling them to continue destroying HIV-infected cells, the researchers said.
"The immune cells that fight HIV naturally produce telomerase during the infection's early phase, but stop once HIV becomes a chronic condition," explained Rita Effros, a professor at UCLA medical school who led the study. "The two compounds switched telomerase back on in the cells."
Earlier research by the UCLA team has showed that inserting thetelomerase gene into the immune cells of an HIV-infected person prevented the cells from aging prematurely. The telomerase enabledthe immune cells to divide indefinitely, stimulated their production of a viral-fighting molecule and prolonged their power to kill HIV-infected cells.
In this study, the scientists isolated immune cells from the blood of HIV-infected persons and cultured the cells with the chemical compounds. They were surprised to see that the compounds produced the same three changes in the cells as those created by the gene therapy.
"We discovered we didn't need to use gene therapy to reactivatethe telomerase and strengthen the immune system's capacity to stave off HIV," said Effros, who is also a member of the UCLA AIDSInstitute. "We were thrilled to see we could create the same changes in the cells without relying on an invasive procedure."
But the researchers did not point out the components of the chemicals, partly because the study was sponsored by Geron, a bio-pharmaceutical firm that also provided the compounds.
Immune cells that battle HIV must constantly divide in order to continue performing their protective functions. The massive amount of division prematurely shortens these cells' ends, or telomeres, ultimately exhausting the immune system.
Previous research showed that telomerase rejuvenates the telomeres and allows the immune cells to remain youthful and active as they replicate under HIV's attack. Drugs that activate telomerase also offer therapeutic potential for a wide spectrum ofdegenerative diseases and chronic conditions in which cellular aging plays a role.
"I'm really excited by our findings. This progress moves us onestep closer to drugs that work by switching telomerase on permanently and keeping the immune cells young and strong in theirfight against infection," Eros said. "These therapies are also easier to develop than gene-therapy drugs."