Chicago — U.S. scientists have developed a strain of green-glowing cats with cells that resist infection from a virus that causes feline AIDS, a finding that may help prevent the disease in cats and advance AIDS research in people.
The study, published Sunday in the journal Nature Methods, involved inserting monkey genes that block the virus into feline eggs, or oocytes, before they are fertilized.The scientists also inserted jellyfish genes that make the modified cells glow an eerie green color — making the altered genes easy to spot.
Tests on cells taken from the cats show they are resistant to feline immunodeficiency virus, or FIV, which causes AIDS in cats.
"This provides the unprecedented capability to study the effects of giving AIDS-protection genes into an AIDS-vulnerable animal," Dr. Eric Poeschla of the Mayo Clinic in Rochester, Minnesota, who led the study, said in a telephone interview.
Poeschla said that besides people, cats and to some extent, chimpanzees, are the only mammals that develop a naturally occurring virus that causes AIDS.
"Cats suffer from this all over the world," he said.
Just as the human immunodeficiency virus, or HIV, does in people, FIV works by wiping out infection-fighting T-cells.
FIV infects mostly feral cats, of which there are half billion in the world, Poeschla said. It is transmitted by biting, largely by males defending their territory, but companion cats are affected as well.
In both humans and cats, proteins called restriction factors that normally fight off viral infections are defenseless against HIV and FIV because the viruses evolved potent counter-weapons. But certain monkey versions of these restriction factors are capable of fighting the virus and the team used one such gene from the rhesus monkey.
For the team, which included collaborators in Japan, the trick was to get the monkey gene for the restriction factor — known as TRIMCyp — into cats to block cells from becoming infected with the virus.
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