Scientists identify factor that may trigger type 1 diabetes

February 11, 2016

A team of researchers, led by investigators at the University of Colorado School of Medicine, have identified a new class of antigens that may be a contributing factor to type 1 diabetes, according to an article published in the current issue of the journal Science.

In autoimmune disease, the key question is why the immune system attacks the body's own tissues. Type 1 diabetes is the autoimmune form of diabetes, in which insulin-producing beta in the pancreas are destroyed by , especially those known as T cells. Insulin is the hormone that regulates levels of glucose in the blood and without insulin, a life-threatening disease results. Currently, there is no cure for type 1 diabetes.

"Our lab studies the type of T cell known as a CD4 T cell," said Kathryn Haskins, PhD, professor of immunology and microbiology and corresponding author of the article. "We have focused on autoreactive CD4 T cells using a mouse model of autoimmune diabetes. We have been especially interested in identifying the antigens that activate these T cells."

Antigens for T cells are pieces of proteins, or protein fragments (peptides) that have to be taken up and presented to the T cells by . Normally, a CD4 T cell is supposed to respond to "foreign" antigens, like a viral peptide. But in autoimmune disease the T cells respond to antigens that are generated in the body. Such proteins and peptides are called autoantigens.

When an autoreactive T cell sees its antigen, it becomes activated and can initiate disease. By identifying those antigens, scientists may be able to use that information to detect autoreactive T cells early in disease, or better yet, in at-risk individuals. If they are able to use the antigens to turn off destructive T cells, they may be able to prevent the disease.

Haskins and others, including fellow corresponding author Thomas Delong, PhD, assistant professor of immunology and microbiology, conducted experiments to analyze the fractions of that contain antigen for autoreactive CD4 T cells in order to identify autoantigens in type 1 diabetes. They discovered a new class of that consist of insulin fragments fused to peptides of other proteins present in beta cells. That fusion leads to generation of hybrid insulin peptides that are not encoded in an individual's genome.

If peptides in the body are modified from their original form, they essentially become "foreign" to the immune system and this may explain why they become targets for the autoreactive T cells. The discovery of hybrid peptides as targets of the immune system provides a plausible explanation of how the is tricked into destroying the body's own beta cells. The discovery may also lead to a better understanding of other .

Explore further: Dendritic cells ensure immune tolerance

More information: "Pathogenic CD4 T cells in type 1 diabetes recognize epitopes formed by peptide fusion," by T. Delong et al. science.sciencemag.org/cgi/doi/10.1126/science.aad2791

Related Stories

Dendritic cells ensure immune tolerance

March 16, 2009

Dendritic cells are essential to the body's immune defenses. Now, Ludwig-Maximilians-Universitaet Muenchen (Germany) researchers show that they also have to protect the body from itself: They help to identify any immune cells ...

Discovery prompts new theory on cause of autoimmune diseases

May 3, 2010

The recent discovery of a protein fragment capable of causing diabetes in mice has spurred researchers at National Jewish Health and the University of Colorado Denver to propose a new hypothesis about the cause of diabetes ...

Researchers prevent type 1 diabetes in lab

January 20, 2015

In new research published in Endocrinology, Thomas Burris, Ph.D., chair of pharmacological and physiological science at Saint Louis University, reports that his team has found a way to prevent type I diabetes in an animal ...

Type 2 diabetes drug can exhaust insulin-producing cells

February 11, 2016

Long-term use of liraglutide, a substance that helps to lower blood sugar levels in patients with type 2 diabetes, can have a deteriorating effect on insulin-producing beta cells, leading to an increase in blood sugar levels. ...

Recommended for you

Diets avoiding dry-cooked foods can protect against diabetes

August 24, 2016

Simple changes in how we cook could go a long way towards preventing diabetes, say researchers at the Icahn School of Medicine at Mount Sinai. A new randomized controlled trial, published online July 29 in the journal Diabetologia, ...

New study reveals a novel protein linked to type 2 diabetes

August 16, 2016

Findings from Boston University School of Medicine (BUSM), which appear in eLife, provide a possible explanation as to why most people who are obese develop insulin resistance and type 2 diabetes. A minority of obese individuals, ...

Gene variant explains differences in diabetes drug response

August 9, 2016

The first results from a large international study of patients taking metformin, the world's most commonly used type 2 diabetes drug, reveal genetic differences among patients that may explain why some respond much better ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.