First-ever vaccine to help control autism-related gut bacteria

Guelph, ON – Researchers at the University of Guelph have created a vaccine for gut bacteria common in autistic children, which they say is the first of a kind. The results were published last week in a study by Brittany Pequegnat and chemistry professor Mario Monteiro, which was published online on April 18 in the journal Vaccine.

They developed a carbohydrate-based vaccine against the gut bacteria Clostridium bolteae. This bacteria is known to play a role in gastrointestinal (GI) disorders, and it often shows up in higher numbers in the GI tracts of autistic children. More than 90% of children with autism spectrum disorders suffer from chronic, severe GI symptoms. Of those, about 75% suffer from diarrhea, according to current literature.

“Little is known about the factors that predispose autistic children to C. bolteae,” said Monteiro. Although most infections are handled by some antibiotics, he said, a vaccine would improve current treatment. “This is the first vaccine designed to control constipation and diarrhea potentially caused by C. bolteae and perhaps control autism-related symptoms associated with this microbe,” he added.

Autism cases have increased almost sixfold over the past 20 years, and scientists don’t know why. Although many experts point to environmental factors, others have focused on the human gut.

Some researchers believe toxins and/or metabolites produced by gut bacteria, including C. bolteae, may be associated with symptoms and severity of autism, especially regressive autism.

Pequegnat, a master’s student, and Monteiro used bacteria grown by Mike Toh, a Guelph microbiology PhD student. The new anti-C. bolteae vaccine targets the specific complex polysaccharides, or carbohydrates, on the surface of the bacteria. The vaccine effectively raised C. bolteae-specific antibodies in rabbits. Doctors could also use the vaccine-induced antibodies to quickly detect the bacteria in a clinical setting, said Monteiro.

The vaccine might take more than 10 years to work through preclinical and human trials, and it may take even longer before a drug is ready for market, Monteiro said.

“But this is a significant first step in the design of a multivalent vaccine against several autism-related gut bacteria,” he added.