Immune protein protects against diabetes

A mechanism by which a person’s immune system is dysregulated in autoimmune diabetes has been found and described in a paper published in Nature Immunology.

Professor Len Harrison and colleagues at the Walter and Eliza Hall Institute of Medical Research (WEHI) have identified that the immune protein CD52 protects the body against excessive or damaging immune responses; it could thus be used to prevent and treat type 1 diabetes and other autoimmune diseases. Such diseases develop when the immune system goes awry and attacks the body’s own tissues.

Professor Harrison explained that CD52 - a well-known and important target for clinical antibodies in treatment regimens - normally sits on the surface of a subset of T immune cells, but its function in the body was, until recently, unknown.

“We have found that when T cells in the immune system are activated they release CD52, and CD52 then dampens down the activity of other immune cells, including T cells,” he said.

“The cells act as an early ‘braking’ mechanism.”

When the CD52 mechanism was blocked in an animal model of type 1 diabetes, the animals rapidly developed the disease. Furthermore, humans at risk for type 1 diabetes were found to “have a deficiency of the cells that make the CD52 factor that causes the dampening down of the immune response.”

“So we think this mechanism is not only just there in the background to dampen down cells, but without it, the immune system may get away and cause autoimmune disease,” said Professor Harrison.

This suggests, says Professor Harrison, that CD52 could be an important therapeutic agent to help prevent or treat type 1 diabetes, multiple sclerosis, rheumatoid arthritis and more. The team is excited at the prospect of developing the discovery to clinical trials and have already received interest from pharmaceutical companies.

Approximately 120,000 Australians have type 1 diabetes and incidence has doubled in the last 20 years. 

“Type 1 diabetes is a lifelong disease,” Professor Harrison said. “It typically develops in children and teenagers, and it really makes life incredibly difficult for them and their families. It also causes significant long-term complications involving the eyes, kidneys and blood vessel damage, and at great cost to the community.”

Professor Harrison says his goal is to prevent and ultimately cure the disease in humans.