Early roots of the virus that causes Aids might be found in a tiger that lived thousands or millions of years ago, new research suggests.
It appears the virus took on a bit of a tiger's genetic material, scientists say, and a remnant of that cat remains in the virus to this day. That tiger, in fact, may have bitten a monkey, setting off an evolution of the virus that ultimately led to its infection of humans.
The finding shouldn't lead to any immediate breakthroughs in Aids treatment, experts say. But it does provide more insight into how the virus works.
How the discovery was made
"Unless you really understand how these viruses work, the exact step-by-step chemical process, then you can't really rationally design a new clever kind of therapy that may be effective against the virus," explained study co-author Robert Bambara, chairman of the University of Rochester's department of biochemistry and biophysics.
Bambara and colleagues made their discovery while trying to figure out how HIV, the virus that causes Aids, hijacks cells and uses them to reproduce. They discovered a gene in the virus that may have come from an ancient tiger that got infected.
"It's a rare and unusual thing that the virus would actually pick up some of the machinery of the cell that it infected," said Bambara.
That bit of machinery, it seems, never went away.
Did a tiger bite a monkey?
The research suggests that HIV may have been a cat virus before it attacked monkeys and humans. Perhaps a tiger bit a monkey and transferred the virus that way, although there could have been another mode of transmission, Bambara said.
Next, researchers hope to determine whether a cousin of the human Aids virus in monkeys, known as simian immunodeficiency virus (SIV), evolved to either have or not have the tiger gene, Bambara said.
If a link exists between the presence of the gene and the strength of the virus, that could be useful to scientists trying to find ways to better treat humans, he said.
However, "it is important to note that this basic research will not have any direct, immediate benefit for anyone with HIV," said Matthew E. Portnoy, program director of the division of genetics and developmental biology at the National Institute of General Medical Sciences.
"What this research could mean," he said, "is that with many more years of basic and clinical research following up these findings, it is possible that new HIV therapies may be developed."
Portnoy added that the research could have ramifications for understanding the swine flu virus, known as H1N1, which has picked up bits of genetic material as it has traveled through species. The study was published in the journal Nature Structural & Molecular Biology. - (HealthDay News, December 2009)