Researchers at the University of Georgia have discovered that a virus commonly found in dogs may serve as the foundation for the next great breakthrough in human vaccine development.
Although harmless in humans, parainfluenza virus 5, or PIV5, is thought to contribute to upper respiratory infections in dogs, and it is a common target for canine vaccines designed to prevent kennel cough. In a paper published recently in PLOS ONE, researchers describe how this virus could be used in humans to protect against diseases that have eluded vaccine efforts for decades.
"We can use this virus as a vector for all kinds of pathogens that are difficult to vaccinate against," said Biao He, the study's principal investigator and professor of infectious diseases in UGA's College of Veterinary Medicine. "We have developed a very strong H5N1 flu vaccine with this technique, but we are also working on vaccines for HIV, tuberculosis and malaria."
PIV5 does not cause disease in humans, as our immune system is able to recognize and destroy it. By placing antigens from other viruses or parasites inside PIV5, it effectively becomes a delivery vehicle that exposes the human immune system to important pathogens and allows it to create the antibodies that will protect against future infection.
This approach not only ensures full exposure to the vaccine but also is much safer because it does not require the use of attenuated, or weakened, pathogens. For example, an HIV vaccine delivered by PIV5 would contain only those parts of the HIV virus necessary to create immunity, making it impossible to contract the disease from the vaccine.
"Safety is always our number one concern," said He, who is also a Georgia Research Alliance distinguished investigator and member of the Faculty of Infectious Diseases. "PIV5 makes it much easier to vaccinate without having to use live pathogens."