Identifying The Underlying Mechanisms Responsible For The Generation Of Pathogenic B Cells In Type 1 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$163,755.00
Summary
Type 1 diabetes (T1D) occurs when the body's own immune system mistakenly attacks and destroys all the beta cells of the pancreas which produce insulin, a hormone essential for regulating sugar levels in the blood. The non-obese diabetic (NOD) mouse develops a form of T1D closely resembling the human disease, and as a model, has led to numerous important insights into its cause. Based on studies in NOD mice, it is now well accepted that a class of cell in the immune system, termed T cells, are r ....Type 1 diabetes (T1D) occurs when the body's own immune system mistakenly attacks and destroys all the beta cells of the pancreas which produce insulin, a hormone essential for regulating sugar levels in the blood. The non-obese diabetic (NOD) mouse develops a form of T1D closely resembling the human disease, and as a model, has led to numerous important insights into its cause. Based on studies in NOD mice, it is now well accepted that a class of cell in the immune system, termed T cells, are responsible for most of the damage to the beta cells in T1D. Recent work in this model, however, has demonstrated that another class of immune cell, termed B cells, also play an important role in T1D as NOD mice made deficient in these cells no longer develop disease. In addition to producing antibodies, B cells are one of the few cell types which are able to take up and present protein fragments in a form recognizable to T cells. Normally, this only leads to the activation of T cells recognising foreign insults, like viruses or bacteria, resulting in their destruction. We have shown that a dangerous population of B cells can arise in NOD mice that can specifically take up beta cell proteins and present them to the T cells, which subsequently become armed to recognise and destroy the beta cells. Just like T cells, B cells that recognize the body's own proteins are normally eliminated in healthy mice and human individuals. This research proposal aims to determine the faulty immune mechanisms that give rise to the beta cell specific B cells in NOD mice. We have also set out to identify the diabetes susceptibility genes which control the generation of this dangerous population of B cells in this model. By understanding how these dangerous B cells are generated in NOD mice, we hope to form the basis for new therapies aimed at inhibiting these cells from forming in T1D susceptible humans, thus preventing the disease at an early stage.Read moreRead less
The Role Of MHC Class I Expression On Pancreatic Ductal Lineage Cells In The Pathogenesis Of Type I Diabetes (TID).
Funder
National Health and Medical Research Council
Funding Amount
$484,300.00
Summary
MHC molecules act as traffic lights to the immune system telling it whether to stop or go, so that only when there is an infection does the immune system receive the signal to destroy target cells. However, the immune system in Type 1 Diabetes patients receives signals to destroy the insulin-producing cells when there is no apparent infection. We aim to determine where the faulty traffic signal occurs and so be in a better position to design intervention strategies to prevent Type 1 Diabetes.
The Role Of Interleukin-21 In The Pathogenesis Of Autoimmune Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$519,000.00
Summary
T cells are a component of our blood (white blood cells) and a major component of the body's defense system against infection, known as immunity. Without T cells, we would fail to resist infection by foreign agents, such as viruses, bacteria and fungi. Autoimmune (type 1) diabetes is a disease in which T cells attack our own pancreatic islet self tissues as if they were foreign. T cells that react against the islets of the pancreas cause destruction of the insulin producing beta cells so that th ....T cells are a component of our blood (white blood cells) and a major component of the body's defense system against infection, known as immunity. Without T cells, we would fail to resist infection by foreign agents, such as viruses, bacteria and fungi. Autoimmune (type 1) diabetes is a disease in which T cells attack our own pancreatic islet self tissues as if they were foreign. T cells that react against the islets of the pancreas cause destruction of the insulin producing beta cells so that the pancreas can no longer make insulin. Diabetes is a life-threatening disease because insulin is a hormone that enables people to get energy from food. Type 1 diabetes is usually diagnosed in childhood and insulin must be administered daily by injection or through a pump in order to survive. Unfortunately, taking insulin doesn t cure diabetes and people continue to suffer from an extensive list of complications affecting most vital organs. Interleukin-21 (IL-21) is a soluble protein that is produced by cells enabling them to communicate with other cells. IL-21 helps cells to produce factors that cause inflammation and assist in clearance of viruses and bacteria from the body. However, our studies show that IL-21 is a major factor in the development of the T cells that destroy beta cells and cause diabetes. Our studies show that IL-21 is over-expressed in an important murine model of spontaneous type-1 diabetes. We have isolated the T cells that cause diabetes and show that they are distinguished from other T cells by very high levels of the receptor for IL-21. This project focuses on the IL-21-responsive T cells that cause diabetes and aims to determine the mechanisms by which the cytokine IL-21 causes destructive immune responses and ways to modulate its production. This project applies basic science to the important public health issue of type 1 diabetes for the development of therapeutic intervention strategies.Read moreRead less