04/28/08

UNITED STATES:  Study Shows Promising New Approach to Thwart HIV

In new research, scientists have identified a protein in human immune system cells that HIV needs to infect the cells, a discovery that could lead to the development of a new drug to fight the virus.

The approach could also provide a new weapon against drug resistance, said Dr. Pamela Schwartzberg of the National Institutes of Health's National Human Genome Research Institute, one of the study's authors. "One of the real problems with treating HIV right now is that most of the drugs that we have are directed against parts of the virus. And with HIV, the virus rapidly mutates its genetic material, its genome," she said. Because of this, researchers have expressed interest in targeting proteins in human cells, which are much less likely to mutate.

The research team interfered with interleukin-2-inducible T cell kinase, or ITK. The protein alerts T-cells to come to the body's defense against invaders like viruses. Once HIV takes over T-cells, it forces them to make viral copies.

In the lab, working with human cells, the team inactivated ITK using two methods: small interfering RNAs, or siRNAS, which can stop certain genes from functioning; and the drug BMS509744, which is known to interfere with the protein but had not been evaluated in the context of HIV. Both methods were successful.

"We didn't completely block [infection] but we certainly severely impaired it. It has minor effects at multiple stages of the HIV life cycle, and together that all adds up to a more profound effect," Schwartzberg said.

Although Schwartzberg said human trials of any drug designed to fight HIV by inhibiting ITK could be years away, the National Institutes of Health and the researchers have filed a patent on the concept of using ITK for this purpose.

The full report, "Selective Targeting of ITK Blocks Multiple Steps of HIV Replication," was published online in the Proceedings of the National Academy of Sciences (04.28.08;doi: 10.1073/pnas.0709659105).

Source: Reuters:: Will Dunham; Courtesy of the CDC National Center for HIV, STD, and TB Prevention