Researchers at UBC and BC Children’s Hospital have found that special proteins called chemokines help keep the immune system from harming healthy tissue — a discovery that may lead to new therapies to stop disorders like type 1 diabetes and multiple sclerosis, or to prevent life-threatening organ rejection in transplant patients.
“This discovery will help us learn more about what immune pathways need to be ‘fixed’ to slow, stop or prevent the harmful immune responses that lead to autoimmune disorders,” says lead investigator Megan Levings, a Professor in the Department of Surgery and investigator at the Child and Family Research Institute.
Immune cells called regulatory T Cells (Tregs) usually prevent the autoimmune attacks that lead to such conditions as type 1 diabetes and multiple sclerosis. Scientists, however, know relatively little about how Tregs work and why they sometimes fail to do their job.
In this study, published today in The Journal of Clinical Investigation, scientists looked at samples taken from mice and found Tregs make proteins called chemokines that attract potentially harmful immune cells. Once the immune cells come into close proximity with the Tregs, the Tregs can send chemical signals that stop them from attacking healthy tissue.
Previous research has shown chemokines draw immune cells to sites of inflammation so the cells can attack pathogens and other dangerous substances, but this was the first proof that chemokines also help keep immune cells in check. “This is an exciting finding because it describes an unexpected way that the immune system regulates itself,” Dr. Levings says.
Scientists also compared blood samples from children with type 1 diabetes to samples from healthy children and found that Tregs in diabetic children produced fewer chemokines than Tregs from healthy children. This suggests that problems with Treg function play a role in the development of diabetes.
“This finding could help us develop new therapies that prevent or treat autoimmune disorders and tissue rejection by ensuring Tregs are making enough chemokines to work correctly,” Dr. Levings said.
Type 1 diabetes develops when the immune system destroys insulin-producing cells in the pancreas, making patients dependant on injections of insulin for life. The condition typically develops during childhood and affects an estimated 31,000 people in British Columbia.
This research was supported by the Canadian Institutes for Health Research and JDRF. The researchers are supported by BC Children’s Hospital Foundation, Canadian Institutes for Health Research, the Canadian Association of Gastroenterology, JDRF, and the Canadian Diabetes Association.