Vaccines possible for prion diseases

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At the University of Saskatchewan’s Vaccine & Infectious Disease Organization (VIDO), Dr. Scott Napper has a lead role in the search for vaccines to treat diseases caused by misfolded proteins known as prions.

His original research focused bovine spongiform encephalopathy in cattle, scrapie in sheep, and chronic wasting disease (CWD) in deer and elk, but his interests have expanded to include several similar human neurodegenerative diseases such as Alzheimer’s, Huntington’s, Parkinson’s, and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s Disease). 

“Is CWD the priority? Yes. Is Alzheimer’s the priority? Yes. We do this work on both human and animal vaccines in parallel,” he said.

Napper explained these diseases result when a protein misfolds and takes on new and devastating characteristics. And once misfolded, the new protein becomes self-propagating.

When the misfold comes in contact with a properly folded version of itself, that protein also misfolds, “so one becomes two and two become four, and you get a cascade of misfolding that ends in deadly disease,” he added.

The Alberta Conservation Association, in partnership with Alberta Environment & Parks and Saskatchewan’s Ministry of Environment, has provided $1.2 million to fund research on an oral vaccine to manage CWD, which poses significant risk to wild cervid populations in four provinces and 28 states.

A team of scientists at four western Canadian universities aim to develop oral vaccines for CWD that can be released in affected habitats. The scientists are working collaboratively with wildlife groups to develop and deliver an effective real-world solution.

On the human front, the Weston Family Foundation through the Weston Brain Institute is providing $1.2 million to Napper and three research colleagues at other Canadian universities to develop a vaccine for misfolded protein diseases in humans. Building on previous developments, the scientists will generate antibodies that attach to misfolded proteins — one has already been selected for pre-clinical development — to prevent disease development, USask said.

The early results are highly encouraging, Napper said. “The pipeline is there, and once we have the target protein, we’ve been able to get the required types of immune responses. All the diseases we’ve talked about have a different target protein but developing the vaccines all use similar processes.”

Napper noted that it’s faster to develop and market a vaccine for animals than for humans, “so it isn’t unreasonable to imagine a CWD vaccine in 7-10 years.” A human vaccine will take longer but Napper is undeterred.

“Our initial success might be to simply slow down the progression of the diseases, but we’ll take incremental successes as they come. There’s hope.”