Mayo Clinic researchers have developed a genome-based immunization strategy to fight feline AIDS (or FIV), and in the process to highlight ways to combat human HIV/AIDS and other diseases. The goal is to create cats with a built-in immunity to the feline AIDS virus, according to the Mayo Clinic and Science Codex.
Feline immunodeficiency virus (FIV) causes AIDS in cats similar to the human immunodeficiency virus (HIV) does in people: by depleting the body's infection-fighting T-cells. The Mayo physicians, virologists, veterinarians and gene therapy researchers, along 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.
Increasingly dogs are being used as models since many illnesses don't need to be induced because they get them naturally. More closely related to us, dogs are better models for that reason as well. And they live longer than mice but not too long where it would take too many years to see what outcomes over many generations will be. Because many types of illnesses in dogs are nearly identical or exactly identical to diseases in people. There are many examples of successes. For example, a osteosarcoma (bone cancer) occurs in particularly large dog breeds. An similar type occurs in people. One drug developed for dogs is now helping children with a type of bone cancer.
It's great that cats are benefiting people, and it's likely this work will also help cats.
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. Though for reasons not completely understood, there FIV is occurring less in cats. Likely it's because the disease is transmitted most often via bites from infected cats, and with more cats being kept indoors that decreases numbers; also for cats outdoors, a vaccine for cats is available.
It's an important point to make that FIV in cats is not a death sentence. Cats with FIV do not require ongoing medication. In fact, while cats with FIV have a damaged immune system and might be more prone to illness, with proactive veterinary care most cats with FIV live long lives and often suffer no more problems than FIV-free cats. Another important point is that there isn't a single known case of FIV in cats transmitted to people. It doesn't happen.
Since the project offers ways introduced genes can protect species against viruses, the hope is that this technology might eventually all assist conservation of wild feline species, all 36 of which are endangered. The technique is called gamete-targeted lentiviral transgenesis -- essentially, inserting genes into feline oocytes (eggs) before sperm fertilization. Succeeding with it for the first time in a carnivore, the team inserted a gene for a rhesus macaque restriction factor known to block cell infection by FIV, as well as a jellyfish gene for tracking purposes.
The method for inserting genes into the feline genome 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.