Type 1 diabetes is a chronic disease characterized by high levels of glucose in the blood that usually begins during childhood or early adulthood. Rotavirus is the most common cause of severe diarrhea among infants and young children. Now a new study from researchers at the University of Melbourne in Australia as published in the journal PLOS Pathogens investigates the role that rotavirus contributes to type 1 diabetes.
For the study, the researchers observed the mechanisms by which rotavirus speeds up onset of type 1 diabetes in mice. Using non-obese diabetic mice, the researchers induced “bystander activation,” which occurs when a virus causes such a strong reaction from the immune system that immune cells begin attacking other cells within the body such as the insulin-producing islet cells in the pancreas, not just the virus.
When the researchers introduced rotavirus into the spleens of the mice, two types of immune cells activated: antibody-producing B cells and dendritic cells. Dendritic cells are antigen-presenting cells whose main function is to process antigen material for presentation on the cell surface to the T cells, thus acting as messengers between the innate and the adaptive immune systems.
The researchers found that rotavirus can cause a specific form of dendritic cell to form that then cause T cells to recognize and destroy the insulin-producing islet cells, thus resulting in type 1 diabetes.
Additionally, the dendritic cells produced very high levels of the immune modulator type 1 interferon, which appears to mediate the bystander effect.
Write the researchers, who believe that the findings of the mouse study should be further investigated on humans, “The role of type 1 interferon signaling in diabetes acceleration following rotavirus infection deserves further analysis.”
Summarizing the findings, the researchers write:
“Understanding how viruses contribute to type 1 diabetes development is vital for disease prevention. Infection of children at-risk of diabetes with the gastrointestinal pathogen rotavirus is associated with increased immune responses to pancreatic islets, leading to the proposal that rotavirus infection may accelerate progression to diabetes.”
Conclude the researchers:
“Our studies suggest that this mechanism of B and T cell activation may occur in RRV-infected mice and contribute to their accelerated diabetes development. A similar mechanism may be involved in the enhanced islet autoantibody responses of children following rotavirus infection.”
The rotavirus vaccine is the only known way to prevent rotavirus infection. Additionally, another study has shown some success in a small trial of a “reverse” vaccine for type 1 diabetes.
Rotavirus Activates Lymphocytes from Non-Obese Diabetic Mice by Triggering Toll-Like Receptor 7 Signaling and Interferon Production in Plasmacytoid Dendritic Cells: http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1003998
Scientists Observe How Rotavirus Infection Can Accelerate Type 1 Diabetes: http://www.medicalnewstoday.com/articles/274700.php
Rotavirus Particles: https://commons.wikimedia.org/wiki/File:Multiple_rotavirus_particles.jpg