Zooming In on Type One

Diabetes occurs when killer T cells destroy insulin producing beta cells

(RxWiki News) Certain white blood cells protect our bodies from a variety of illnesses. But what happens when these cells turn against us? In some cases, it leads to type 1 diabetes.

People develop type 1 diabetes when killer T-cells (a type of white blood cell) attack the cells in the pancreas that produce insulin, a hormone that manages blood sugar levels.

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Researchers already know that T-cells play a role in the development of type 1 diabetes. Yet, there is little understanding of the mechanisms that drive this process.

In a recent study, Professor Andy Sewell, of Cardiff University's School of Medicine, and colleagues set out to gain more insight on the role of T-cells in the development of type 1 diabetes. Understanding how diabetes develops could lead to better diagnosis and treatment.

Insulin is a hormone that controls blood sugar. Without it, cells would not be able to use blood sugar for energy. Insulin is made by cells in the pancreas called beta cells. In people with type 1 diabetes, the pancreas makes little or no insulin, which is fatal if left untreated.

According to Professor Sewell, "The mechanism by which the body attacks its own insulin producing cells in the pancreas is not fully understood. Our findings show how killer T-cells might play an important role in autoimmune disease like diabetes and we've secured the first ever glimpse of the mechanism by which killer T-cells can attack our own body cells to cause disease."

Usually, T-cells in our bodies protect us from disease. However, the research by Professor Sewell and colleagues shows that T-cells can mistakenly destroy beta cells. When this happens, a person can develop type 1 diabetes.

The study reveals for the first time how T-cells damage beta cells and could lead to a new understanding of the cause of type 1 diabetes.

"This knowledge will be used in the future to help us predict who might get the disease and also to develop new approaches to prevent it," says study co-author Professor Mark Peakman, of the National Institute for Health Research Biomedical Research Centre in London. "Our aim is to catch the disease early before too many insulin-producing cells have been damaged."

The findings show that the killer T-cell receptor (the part of the cell that recognizes foreign invaders in the body) uses an unusual type of binding in order to recognize cells that make insulin.

The researchers believe that this abnormal binding protects T-cells from being identified as auto-reactive T-cells, or cells that mistakenly attack the body.

Professor Sewell and colleagues made these findings by isolating a T-cell from one patient with type 1 diabetes.

The study was supported by the UK Biotechnology and Biological Sciences Research Council and the Juvenile Diabetes Research Foundation. The results are published in the journal Nature Immunology.

Review Date: 
January 16, 2012