A professor in Melbourne, Australia, who is on a mission to find a cure for type 1 diabetes, believes that the answer, or part of it, lies with an immune suppressor protein called CD52. And if it works for type 1 diabetes, then it may well work for other immune disorders, such as multiple sclerosis and rheumatoid arthritis, where disruption in the balance of different kinds of T cell in the immune system causes it to attack the body's own healthy tissue.

In a new study published this week in Nature Immunology, diabetes researcher and professor Len Harrison and colleagues from the Walter and Eliza Hall Institute's Molecular Medicine, suggest it may be possible to use CD52, which naturally stops the immune system overreacting and killing insulin-producing pancreatic cells, to stop or even reverse type 1 diabetes in the early stages, before all the insulin-producing cells have been destroyed.

In a statement to the media Harrison says:

"Immune suppression by CD52 is a previously undiscovered mechanism that the body uses to regulate itself, and protect itself against excessive or damaging immune responses."

Type 1 Diabetes Is An Autoimmune Disease

Type 1 diabetes is an autoimmune disease that typically starts in childhood and teen years. It happens because an imbalance in the immune system causes it to destroy insulin-producing cells in the pancreas. Without insulin, the body cannot regulate blood sugar, and if this gets too high, it causes serious damage to organs.

It is a "lifelong disease", says Harrison, adding that in Australia alone there are around 120,000 people with it, a number that has doubled over the last two decades.

He says the disease makes life "incredibly difficult" for children and teenagers, and also for their families.

"It also causes significant long-term complications involving the eyes, kidneys and blood vessel damage, and at great cost to the community," he adds.

Currently people with type 1 diabetes have to have insulin injections for life, and they must also make sure that their blood glucose levels stay balanced.

However, there is a possibility this may change, as suggested by a recent report of a study, where scientists describe how they developed an extended insulin-release system comprising an injectable gel of nanoparticles.

The Role of T Cells In Autoimmune Disease

There is a group of cells in the immune system called T cells. These normally seek out and destroy undesirable cells and material that may pose a danger to the body, such as invading bacteria.

There are different kinds of T cell, each performing a slightly different role and primed to find different kinds of target.

In healthy people, T cell populations interact and keep the immune system in balance. When this balance is upset, the T cells misbehave, and do things like attack healthy cells as if they were dangerous pathogens. This is the principle of autoimmune disease.

One of the mechanisms through which the T cells keep the immune system in balance is by exchanging chemical messages.

This study shows how one of these chemical messages is transported by CD52, a protein that can "dock" onto receptors located on the surfaces of certain T cells:

"We found that human and mouse antigen-activated T cells with high expression of the lymphocyte surface marker CD52 suppressed other T cells," write the authors.

CD52 Has Great Potential For Preventing and Treating Type 1 Diabetes and Other Autoimmune Diseases

Harrison says their discovery of how CD52 works as an immune suppressor holds great promise for preventing and treating autoimmune diseases like type 1 diabetes.

He and his colleagues suggest CD52 plays a key role in suppressing immune activity in the early stages of the immune response.

He explains how T cells that have or release high levels of CD52 are essential for keeping the immune system in balance. They act like an "early braking mechanism", he adds.

With lab mice bred to be prone to diabetes (but not the one caused by obesity), which is used a model for type 1 diabetes, the researchers showed that removing CD52-producing immune cells led to rapid development of diabetes.

"We think that cells that release CD52 are essential to prevent the development of autoiummune disease, and that CD52 has great potential as a therapeutic agent," Harrison concludes.

He and his team are "excited" by the prospect of taking CD52 to clinical trials as soon as possible. He says some pharma companies have already expressed some interest.

Harrison says his goal is to prevent and cure type 1 diabetes.

"In animal models we can prevent and cure type 1 diabetes," he says, adding that he wants these results to "be translatable into humans, hopefully in the not-too-distant future".

Funds from the National Health and Medical Research Council of Australia and the Victorian Government helped finance the study.





Written by Catharine Paddock PhD