Development of an oral vaccine for piglets: A platform technology
Project:11-228 - Researcher: Heather Wilson
Researcher: Heather Wilson, Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan.
Project start: 2012 Project Completion: 2014
Traditional pig vaccines must be injected into the pig in order to stimulate the animal’s immune system to produce a protective response against pathogens such as viruses and bacteria. However these systemic vaccines do not induce an immune response on the mucosal surfaces. As pigs can be exposed to a large number of pathogens through the digestive tract, researchers from the Vaccine and Infectious Disease Organization (VIDO), at the University of Saskatchewan, wanted to design a vaccine that would allow the pig’s immune system to immediately recognize and attack pathogens that try to enter through the mucosal surfaces of the digestive tract. This was a challenging goal as the immune system would need to recognize and differentiate between all of the harmless and potentially harmful elements the pig ingests.
Rather than testing this concept for a new oral vaccine by challenging pigs with a disease, the researchers created and administered an oral vaccination against egg protein for the preliminary testing. Shortly after birth, the vaccine was squirted into the pig’s mouth. At this age the digestive surfaces of the piglet are still permeable so that antibodies passed on from the sow’s milk can be absorbed. This allowed the vaccine to be captured by the immune cells that are responsible for mucosal surface protection. The trial demonstrated that when the egg protein vaccine was given alone, the pigs showed tolerance to the protein after receiving a booster vaccine several weeks later. When the vaccine was given with an adjuvant, the pigs showed a protective immune response when they received a booster of the vaccine. The most significant protective response provided was seen in body systems like the bloodstream, similar to traditional vaccines, but some protective responses were also seen at digestive surfaces. With these positive results, researchers then focused on trying this new type of oral vaccine against routine pig diseases. They also began investigating how to further improve responses at digestive surfaces. If successful, this type of vaccine could be useful for protecting young pigs from infection while reducing the number of pigs carrying and shedding pathogens in a herd.