Protein resistant to AIDS discovered

ASSOCIATED PRESS

Scientists say they have discovered how some monkeys resist infection by the AIDS virus, a finding that might lead to a treatment that blocks HIV in people.

Researchers found that once HIV enters monkey cells, it encounters a protein that stifles its attempts to replicate. That stops the virus from spreading in the animal.

“This is really important because it will help build a basis for hammering the virus before it gets started,” said Paul Luciw, a microbiologist who specializes in AIDS research at the University of California at Davis.

The protein, called TRIM5-alpha, was identified in rhesus macaques by a team of Harvard researchers at the Dana-Farber Cancer Institute in Boston. It is not clear exactly how the protein acts against HIV, said Dr. Joseph Sodroski, who led the Harvard study published today in the journal Nature.

Humans have their own version of TRIM5-alpha, but it’s not as effective as the monkey version in countering HIV. However, researchers may be able to design a drug that makes the protein work better, Dr. Sodroski said.

“We expect that now that we’ve identified this protein factor, it is likely we’ll find ways to manipulate it and increase its potency,” Dr. Sodroski said, “and we hope to stimulate our own natural resistance to HIV by doing so.”

The mechanism even may work against other viruses, he said.

“What we’re really uncovering is the first example of a natural system of defense that may be operating against other viruses besides HIV,” Dr. Sodroski said. “We’re looking at ‘example one’ here, and I highly doubt it will be the only example in nature.”

HIV normally enters a cell and hijacks its “factory” for making proteins. It orders the machinery to churn out proteins to make new copies of HIV, which then leave to infect other cells.

The monkey protein blocks this process, apparently by interfering with HIV’s attempts to remove the coating that surrounds its genetic material, researchers said. This coating must be shed before HIV can insert its genetic material into the cell’s own DNA, a key step in replication.

The Nature report could help researchers test the effectiveness of a potential HIV vaccine on animals now that scientists have a better understanding of why monkeys resist the disease, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

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