UF researcher develops aids vaccine for cats

March 22, 2002

GAINESVILLE, Fla. – In a major scientific breakthrough, a University of Florida researcher has developed a feline AIDS vaccine that the federal government has approved for commercial use.

The U.S. Department of Agriculture granted a license last week that will enable Kansas-based Fort Dodge Animal Health to market the product developed by Janet Yamamoto, a professor at UF’s College of Veterinary Medicine who co-discovered the feline immunodeficiency virus. The FIV vaccine is expected to be available to cat owners – through their veterinarians – as early as this summer. Fort Dodge Animal Health is a division of New Jersey-based Wyeth pharmaceuticals.

“This is the first product to ever be made available for preventing this viral infection,” said USDA spokesperson Jim Rogers. “For that matter, it’s the first time any type of vaccine to prevent any type of animal immunodeficiency virus infection has ever been approved for commercial use.”

FIV has many biological similarities to the human immunodeficiency virus, or HIV, the cause of human AIDS. For that reason, strategies and procedures for protecting cats from FIV are expected to aid in the development of human AIDS vaccines.

FIV attacks a cat’s immune system, causing AIDS in cats worldwide. Between 2 percent and 25 percent of the global domestic cat population is believed to be infected with the virus, according to the USDA. The numbers vary due to geographic region, ages of the cats, whether they are kept outdoors and other health problems they may have.

“It is generally believed that transmission of FIV takes place through bite wounds inflicted during fighting, and no cat-to-human transmission has ever been reported ages of the cats, whether in the literature,” Yamamoto said. “However, we are looking into this possibility.”

She added that cats with FIV develop symptoms in three stages.

“In the acute initial stage, cats show loss of appetite, transient fever, lethargy and have a low white blood cell count,” Yamamoto said. “Many cats recover from the initial phase and become lifelong carriers of the virus.

In the second stage, the cats exhibit no overt symptoms. In the third stage, however, cats experience severe weight loss, and secondary infections that become resistant to treatment or frequently recur.”

Yamamoto’s vaccine technology is based on viruses from cats called “long-term nonprogressors,” so named because the animals have been infected with FIV but take a long time to show symptoms of the disease.

“This vaccine is truly international and unique because it is composed of two different FIV strains from two different subgroups of the virus from both the United States and Asia,” Yamamoto said. “These strains take a long time to cause disease, and once symptoms do occur, the disease is milder.”

This interests Yamamoto because she believes long-term nonprogressor cats are probably capable of mounting effective immune responses against the FIV virus, since the virus takes so long to cause disease.

“Instead of rapidly destroying the immune system, the virus hangs around at low levels in these cats and stimulates the immune system, allowing it to respond more effectively,” said Yamamoto, whose research has received grant support from the National Institutes of Health.

“Dr. Yamamoto has always been in the front line of research about FIV and the development of vaccines against feline AIDS, starting from the first identification of the virus in 1986,” said Dr. Mauro Bendinelli, a professor at the University of Pisa in Italy.

“Her achievements in the area are indeed outstanding. The fact that USDA has approved Janet’s FIV vaccine for commercial use is an extremely important step forward in the area of vaccines against lentiviruses in general, since it represents the first vaccine to be considered of practical value by an official regulatory body,” Bendinelli said. “I expect this will boost interest in the development of other lentiviral vaccines, including HIV.”

Dr. Steve Chu, senior vice president for global research and development at Fort Dodge Animal Health, called Yamamoto’s vaccine technology, “a scientific breakthrough for lentivirus vaccine and disease prevention.”

Yamamoto first discovered the virus in 1986 along with a former colleague, Dr. Niels Pedersen of the University of California, Davis. Yamamoto has continued to study the virus and its pathogenesis, which provided the foundation for developing the vaccine.

UF and the Regents of the University of California jointly hold the patents for the FIV vaccine, and the two institutions have reached agreement with Fort Dodge to explore the use of the FIV vaccine for commercial applications, according to Bin Yan, assistant director of life sciences at UF’s Office of Technology Licensing.

“In our experience, a vaccine made using my approach is safe,” Yamamoto said. “However, it is critical that further studies of our vaccine take place on an international level to assess whether protection against worldwide strains of feline AIDS is possible, and whether vaccines composed of viruses from these long-term nonprogressor cats are effective.”