Australia: Understanding HIV's Infectious Grip

Australian scientists believe they know how HIV can establish itself in latent form in the human body, a mystery that has presented the foremost barrier to eradicating the virus by highly active antiretroviral therapy. The study proposes a mechanism through which HIV persists in latently infected resting CD4+ T cells.

"Once HIV gets into these cells, the virus can then go to sleep," said study co-author Sharon Lewin, director of The Alfred's Infectious Diseases Unit and co-head of the Burnet Institute's Center for Virology.

"These silently infected cells are not cleared by anti-HIV drugs or the immune system," Lewin said. "Once a patient stops the anti-HIV drugs, the virus can then wake up and get going again. Understanding this mechanism will enable new treatment options to be developed which could block latent infection."

"We have shown that a family of proteins, called chemokines, that guide the resting cells through the blood and into the lymph node tissue can ‘unlock the door' and allow HIV to enter and set up a silent or latent infection," Lewin said.

In practice, the finding could help the development of potent new HIV treatments, possibly blocking latency while clearing active infection, Lewin said.

The global scientific community has "been working on HIV for close to 30 years, and it's really only now that we're beginning to see that a cure for HIV might be achievable and needs to be a major scientific priority," said Brendan Crabb, director of the institute.

The study, "Establishment of HIV-1 Latency in Resting CD4+ T Cells Depends on Chemokine-Induced Changes in the Actin Cytoskeleton," was published in the Proceedings of the National Academy of Science (2010;107(39):16934-16939).

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