( V attaches to this T-cell by first land...)Study IDs protein that inhibits HIV from growing in cell cultures

"People with GBV-C have a slower rate of destruction of these T-cells," said Stapleton, who also is director of the Division of Infectious Diseases at the Iowa City VA and UI.

The current study shows that the newly identified protein, NS5A, inhibits HIV in part by decreasing the number of CD4 receptors available to HIV. With fewer places for HIV to "dock," less HIV enters the cells to inflict destruction.

However, Xiang cautioned, this is only part of the story, and the researchers must continue work to understand how the NS5A protein exerts its total effect.

"Before NS5A can be used for any kind of therapy, we need to further map it," Xiang said. "We need to zero in to see what region has the critical effect on HIV inhibition."

Once that is accomplished, the team will seek to develop small molecular drugs that mimic the inhibiting action.

Stapleton noted that GBV-C is not toxic to T-cells and is not associated with any human disease. As a result, the U.S. Food and Drug Administration does not require that blood donations be screened for this common virus.

Up to 3 percent of healthy blood donors in the United States have active GBV-C infection. An additional 12 percent have antibodies indicating past exposure at the time of donation. Because the GBV-virus is transmitted through bodily fluids, as is HIV, many HIV-positive individuals have evidence of past or present infection with GBV-C.

Stapleton and Xiang first began studying the GBV-C and HIV connection because they were skeptical of earlier studies published in the mid-1990s.

"It was a strange story," Stapleton said. "Who would have thought a virus floating around in a lot of people does not make them sick but could significantly
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Source:University of Iowa