Mayo Clinic teams with glowing cats against FIV/AIDS

New technique gives cats protection genes

Biology News

Cats with the protective gene glow green.

Mayo Clinic researchers have developed a new immunization strategy to fight feline AIDS and illuminate ways to combat human HIV/AIDS and other diseases. The goal is to create cats with intrinsic immunity to the feline AIDS virus. The findings appear in the current online issue of Nature Methods.

Feline immunodeficiency virus (FIV) causes AIDS in cats as the human immunodeficiency virus (HIV) does in people: by depleting the body's infection-fighting T-cells. The feline and human versions of key proteins that defend mammals against virus invasion are ineffective against FIV and HIV respectively. The Mayo team devised a way to insert effective monkey versions of them into cats.

"One of the best things about this biomedical research is that it is aimed at benefiting both human and feline health," says Eric Poeschla, M.D., leader of the study. "It can help cats as much as people."

Dr. Poeschla treats patients with HIV and researches how the virus replicates. HIV/AIDS has killed over 30 million people and left countless children orphaned, with no effective vaccine on the horizon. Less well known is that millions of cats also suffer and die from FIV/AIDS each year. Since the project concerns ways introduced genes can provide protection against viruses, the knowledge and technology it produces might eventually assist conservation of various endangered cats living in the wild.

The technique is called gamete-targeted lentiviral transgenesis, which involves inserting genes into eggs before sperm fertilization. Succeeding with it for the first time in a carnivore, the team inserted a gene for a rhesus macaque gene known to block cell infection by FIV, as well as a jellyfish gene for tracking purposes. The latter makes the offspring cats glow green, which makes it easy to tell which cats have been genetically altered.

The macaque gene, TRIMCyp, blocks FIV by attacking and disabling the virus's outer shield as it tries to invade a cell. The researchers know that works well in a culture dish and want to determine how it will work in vivo.

The method for inserting protective genes is highly efficient, so that virtually all offspring have the genes. And the defense proteins are made throughout the cat's body. The cats with the protective genes are thriving and have produced kittens whose cells make the proteins, thus proving that the inserted genes remain active in successive generations.