Since it was first reported in June 1985, the HIV/AIDS virus has claimed 35 million lives worldwide. To this day there is no effective vaccine on the horizon. But steps have been taken to fight this dreaded virus and they have been huge thanks to awareness campaigns that brought to light the impact of the virus on people’s lives. However, and little did we know, it is not only human beings who can suffer from the virus. Even cats. Yes. Cats. And it is called feline immunodeficiency virus (FIV).
Recently, researchers from Mayo Clinic have developed what they call a genome-based immunization strategy to fight feline AIDS. The strategy seeks to illuminate ways to combat human HIV/AIDS and other diseases. The goal is to create cats with intrinsic immunity to the feline virus.
FIV causes AIDS in cats as HIV does in people – it depletes the body’s infection-fighting T-cells. The versions of key proteins – restriction factors – found in both cats and humans try to defend mammals against virus invasion. However, they remain ineffective against FIV and HIV respectively.
The team of physicians, virologists, veterinarians and gene therapy researchers at the Mayo Clinic together with collaborators in Japan, sought to mimic the way evolution normally gives rise over vast time spans to protective protein versions. They devised a way to insert effective monkey versions of them into the cat genome.
Poeschla treats patients with HIV and researches how the virus replicates. Since the project concerns ways introduced genes can protect species against viruses, the knowledge and technology it produces might eventually assist conservation of wild feline species, all 36 of which are endangered.
The technique Mayo Clinic researchers are using is called gamete-targeted lentiviral transgenesis. It modifies the genome and blocks FIV by attacking and disabling the virus’s outer shield as it tries to invade a cell.
What happens is that genes are inserted into feline oocytes (eggs) before sperm fertilization. The first time this technique was used to a cat, it was successful after the team inserted a gene for a rhesus macaque restriction factor known to block FIV cell infection. It also used a jellyfish gene for tracking purposes. The latter makes the offspring cats glow green.
The method for inserting genes into a cat’s genome is highly efficient virtually making all offspring have the genes. Through this 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.
The researchers know that works well in a culture dish and want to determine how it will work in vivo. The specific transgenesis approach will not be used directly for treating people with HIV or cats with FIV, but it will help medical and veterinary researchers understand how restriction factors can be used to advance gene therapy for AIDS caused by either virus.