Study Looks At Possible Vaccines Developed From Canine Virus

Connie K. Ho for — Your Universe Online

Dogs are known to be man´s best friend. However, on closer inspection, canines could provide even more than friendly companionship and become a gateway to infection protection. In particular, researchers from the University of Georgia (UGA) recently revealed that a common virus found in dogs could possibly help develop novel vaccines to treat fatal human diseases.

The virus, known as a parainfluenza virus 5 (PIV5), is usually targeted by canine vaccines to stop kennel cough and respiratory infections from developing. Researchers believe that the virus could be a foundation to help protect humans against diseases that have defended against vaccines in the past.

“We can use this virus as a vector for all kinds of pathogens that are difficult to vaccinate against,” explained the study´s principal investigator Biao He, a professor of infectious diseases at UGA’s College of Veterinary Medicine, in a prepared statement. “We have developed a very strong H5N1 flu vaccine with this technique, but we are also working on vaccines for HIV, tuberculosis and malaria.”

As PIV5 doesn´t lead to the development of diseases in humans, the team of investigators was able to place antigens from other viruses or parasites inside PIV5 so that it can act as a vehicle to deliver essential pathogens that can produce antibodies. These antibodies can then defend the body against possible infections. The researchers believe that this method allows for full exposure to the vaccine in a safer manner.

“Safety is always our number one concern,” remarked He, who also serves as a Georgia Research Alliance distinguished investigator, in the statement. “PIV5 makes it much easier to vaccinate without having to use live pathogens.”

Researchers believe that, while utilizing viruses to deliver pathogens is not new, there have been difficulties with previous experiments. In particular, if humans or animals are already immune to the virus utilized for delivery, then the vaccine may not be effective. As a result, the immune system may destroy the virus too quickly.

“Pre-existing immunity to viruses is the main reason most of these vaccines fail,” noted He, also a member of the Faculty of Infectious Diseases.

In the current study, the team of investigators showed that immunity to PIV5 didn´t change the effectiveness of the virus in acting as a delivery mechanism. They discovered that a single dose inoculation with PIV5 was able to defend the mice against a strain of influenza that was related to the seasonal flu. Another single dose of an experimental vaccine was able to defend the mice against the H5N1 virus, otherwise known as the bird flu.

Overall, the researchers have studied this topic for the past 154 years and believe that the research findings will be a jumping off point in terms of developing vaccines that can protect both humans and animals.

“I believe we have the best H5N1 vaccine candidate in existence,” concluded He in the statement. “But we have also opened up a big field for a host of new vaccines.”

The findings on PIV5 were recently featured in the journal PLOS ONE.