According to an article published in Science, the website of American Association for the Advancement of Science, human reovirus orally infected resulted in an immune response against gluten and led to symptoms of celiac disease in the rodents.
Reoviruses, avirulent pathogen commonly infect humans and mice asymptomatically. Bouziat et al. found that immune responses to two gut-infecting reoviruses -Type 1 Lang (T1L), which naturally infects the gut of both mice and humans, and a version of type 3 Dearing (T3D) genetically modified to be capable of infecting the intestine, take different paths in mice. T1L infection resulted in higher levels of antibodies against the virus and an inflammatory immune response against dietary gluten or ovalbumin when the mice were fed a diet that included these proteins, team found.
The mouse gut when exposed to a new benign food antigen, stimulated T-regulatory cells that prevent the immune system from attacking the antigen as it would a pathogen. But the researchers saw the evidence in the T1L-infected mice, an interferon response to both the virus and the dietary proteins responsible for blocking the normal T-regulatory cell pathway as well as an effector T-cell response against the dietary proteins.
In a mouse celiac disease model, T1L infection also derailed the animals’ gluten tolerance and resulted in an inflammatory response including the activation of the transglutaminase 2 enzyme, which increases the affinity of gluten for immune cells and is thought to stimulate pathogenesis.
“We now have a clue that reovirus might be one trigger for celiac disease,” said study co-author Terence Dermody, chair of the department of pediatrics at the University of Pittsburgh School of Medicine in Pennsylvania. “The potential mechanism is that when gluten is introduced right at the time that an asymptomatic reovirus infection is taking hold, that causes the immune system to treat the gluten as foreign, eliciting an immune response against it”, he responded to a website The Scientist .
The team found the higher levels of anti-reovirus antibodies in people with the disorder compared to those without it. Follow-up study is required, the researchers noted, as there was no clear correlation of antibody levels and evidence of an inflammatory response. They suspect children to already be infected at the time they are introduced to gluten.
Researchers are further investigating on how reoviruses cause inflammation in the gut that can lead to celiac disease, plus whether other viruses might do the same.
Alessio Fasano, a pediatric gastroenterologist who studies celiac disease at the Massachusetts General Hospital for Children in Boston ,who was not involved in the work said, ““If confirmed by clinical studies, this link between celiac disease and reovirus is exciting because it identifies a possible target for vaccine prevention. At the same time, it’s disappointing because vaccine prevention in individuals with asymptomatic viral infections who are at risk of celiac disease would be challenging.”