March 14, 2008
PhD student Peter Hedlin talks about his work on a team trying to find a way to stimulate animal and human immune systems to fight BSE (mad cow disease) and other wasting diseases.
Photo by Colleen MacPherson
By Brette Ehalt
When PhD student Peter Hedlin isn’t playing cello with the U of S Amati Quartet, he’s working to find a vaccine for mad cow disease, which may, some day, point to a treatment for other devastating wasting diseases in both animals and humans.
Since 2006, Hedlin has been working with a team, led by Scott Napper, on an immunotherapy project for Bovine Spongiform Encephalopathy (BSE) at VIDO. Together, they’ve been trying to find a way to stimulate the immune system so that it will attack the molecules responsible for causing BSE, commonly called mad cow disease.
“The interesting thing,” says Hedlin, “is that these disease-causing molecules, called prions, are almost identical to the ones that cause Scrapie in sheep, Chronic Wasting Disease (CWD) in deer and elk, and Creutzfeldt-Jakob’s Disease (CJD) in humans. So, in theory, if this project is successful for BSE, it may also be successful for the others.”
Hedlin explains that prion proteins are present in two forms: prion cellular (PrPc), the “normal” form found in humans and animals; and prion scrapie (PrPSc), the infectious form found in animals with BSE. Once PrPSc enters the body, however, it converts the normal form into the infectious form.
“This makes it really tricky for vaccine development because we have to try and get the immune system to attack only the infectious form, not the regular form. Plus,” continues Hedlin, “prions have no nucleic acid like DNA or RNA, making them different from bacteria, viruses, and fungi, the causes of all other infectious diseases that we know about.”
In the lab, the team has been making different manipulations to a small piece of protein—previously identified by other collaborators—with the hope that one design will produce an immune response that is strong enough to provide animals with protection from the disease. So far, testing has been done primarily on sheep and mice. Following some promising results, they have expanded their animal trials to include cows, elk, and deer.
“But,” notes Hedlin, “until infection studies are conducted, we won’t be able to determine if the immune responses that we are generating will actually protect against the disease. Because we do not yet have INTERVAC at our service, infection trials will have to be conducted by some of our collaborators.”
Ultimately, the team’s goal is to create a vaccine that will be able to prevent the development of prion diseases in previously unexposed animals. If such a vaccine is created, it could also be able to slow or stop the progression of the disease in animals that have previously become infected.
Originally from Saskatoon, Hedlin completed his B.Sc. and M.S. in Microbiology at the U of S. Before returning as a PhD student in the Department of Biochemistry, Hedlin studied music in Victoria with the Lafayette String Quartet. Now, he plays with the U of S Amati Quartet in Residence. Their year-end concert will take place March 15 in Convocation Hall at 8 pm.
Brette Ehalt writes profiles of grad students for the College of Graduate Studies and Research.