CD4 T Cell-mediated Tolerance And Autoimmunity To The Gastric H/K ATPase In Genetically Manipulated Mice
Funder
National Health and Medical Research Council
Funding Amount
$295,780.00
Summary
The immune system is designed to protect us from foreign pathogens such as bacteria and viruses. However, the system is not prefect and sometimes attacks an individual's own tissue (termed autoimmunity). Autoimmunity is not uncommon in the population, including diseases such as diabetes, rheumatoid arthritis and pernicious anaemia, to name a few. To study the details associated with why and how the immune system can turn on the host, we use animal models which mimic the human diseases. The model ....The immune system is designed to protect us from foreign pathogens such as bacteria and viruses. However, the system is not prefect and sometimes attacks an individual's own tissue (termed autoimmunity). Autoimmunity is not uncommon in the population, including diseases such as diabetes, rheumatoid arthritis and pernicious anaemia, to name a few. To study the details associated with why and how the immune system can turn on the host, we use animal models which mimic the human diseases. The model we use is a mouse model for autoimmune gastritis which is an organ-specific autoimmune disorder of the stomach. People with autoimmune gastritis produce a specific autoimmune response directed at the acid secreting cells of the stomach call parietal cells. Parietal cells also produced a substance called intrinsic factor which is needed for the absorption of vitamin B12 from the diet. The lack of vitamin B12 uptake results in abnormal red blood cell formation and anaemia; hence the term pernicious anaemia. One of the unanswered questions associated with the immune system is what regulates the whole system so that it does not induce autoimmunity in everyone. The mechanisms which control or prevent autoimmunity is the subject of much debate. There is good evidence that regulation of the immune system is performed by specific suppression by regulatory cells. Many important question about these cells remain unanswered. For example, it is not known how these cells are generated or how they prevent the autoreactive cells from performing their harmful behaviour. Using our animal model for autoimmune gastritis, we are addressing some of the questions which surround the events which induce and protect us from autoimmunity. By using mice in which most of the lymphocytes in the circulation are of the same specificity (TCR-transgenic), we can follow the fate of those cells and look for cells with different characteristics; such as the ability to supress an immune response.Read moreRead less
Apoptotic Pathways In Pancreatic Beta Cells Leading To Type 1 Diabetes And Transplant Rejection
Funder
National Health and Medical Research Council
Funding Amount
$535,333.00
Summary
The destruction of insulin-producing beta cells in the pancreas by immune cells leads to the need for daily insulin injections in patients with type 1 diabetes. This project aims to understand how beta cells are destroyed. A knowledge of the process by which this occurs will indicate ways we can protect these cells. Our previous work has suggested strategies that may protect beta cells, and we aim to test these. Such protection may eventually allow beta cell replacement by transplantation.
A T-cell Based Approach To Identifying Islet Antigens In Human Type 1 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$404,400.00
Summary
Autoimmune diseases arise when the immune system, which protects us from infections and cancer, attacks healthy tissues. Nobody knows why the immune system mistakes healthy for unhealthy tissue. The immune system's T cells are prime suspects because they play a central role in controlling the immune response. Hence, the aim of this work is to understand what human T cells see in healthy tissues that may lead them to cause autoimmune diseases like type 1 diabetes.
Functional Genomic Analysis Of NK And NKT Cell Immune Control Of Autoimmunity
Funder
National Health and Medical Research Council
Funding Amount
$692,040.00
Summary
The major populations of white blood cells responsible for learned immunity to are the B cells, which make antibody against microorganisms like bacteria, and the T cells, which kill virally infected cells and help B cells produce antibody. The T and B cells occasionally attack the body s own tissues, resulting in autoimmune disease. These diseases include type 1 diabetes, lupus, and anaemia, and collectively represent the third commonest cause of morbidity and mortality in humans. The major reas ....The major populations of white blood cells responsible for learned immunity to are the B cells, which make antibody against microorganisms like bacteria, and the T cells, which kill virally infected cells and help B cells produce antibody. The T and B cells occasionally attack the body s own tissues, resulting in autoimmune disease. These diseases include type 1 diabetes, lupus, and anaemia, and collectively represent the third commonest cause of morbidity and mortality in humans. The major reason why autoimmunity occurs is thought to be due to a failure in the mechanisms responsible for controlling such unwanted responses. Two other populations of white blood cells are involved in this regulation, termed NK and NKT cells, each of which release important cell hormones. The current project is designed to test whether defects in NK and NKT cells lead to autoimmune disease. For this purpose a special strain of mice (NOD mice) will be used. The reasons for their selection are: 1) they are highly susceptible to a range of autoimmune diseases including diabetes, lupus and anaemia, and 2) we and others have found that they are deficient in both NK and NKT cells. The proposed experiments are divided into two groups, one designed to characterise the nature of the defects in these cells and the other to identify the genes responsible for them. In this way it should be possible to shed light on the genetic basis of autoimmune diseases in general. The approach to be used involves sophisticated techniques of genetic analysis, which require production of special congenic lines of mice. These mice are like NOD mice but carry in addition to NOD genes genetic regions from a non-autoimmune strain with the potential to correct the defects in NK and NKT cells. In this way, it should be possible to pinpoint the disease susceptibility genes involved in causation of autoimmunity and to work out how they affect NK and NKT cells.Read moreRead less
Genetic And Biochemical Mechanisms Dysregulating CD4 T Cell Tolerance In Organ-specific Autoimmunity
Funder
National Health and Medical Research Council
Funding Amount
$456,000.00
Summary
This project will analyse mechanisms that regulate CD4 T cells and normally prevent the immune system from attacking parts of our own body. Unknown errors in the control of T cells result in autoimmune diseases such as Type 1 diabetes, multiple sclerosis, and thyroid disease, where T cells damage or destroy vital organs. In order to develop rational, specific methods for treating and preventing these diseases, it is necessary to identify and understand the genetic and biochemical mechanisms that ....This project will analyse mechanisms that regulate CD4 T cells and normally prevent the immune system from attacking parts of our own body. Unknown errors in the control of T cells result in autoimmune diseases such as Type 1 diabetes, multiple sclerosis, and thyroid disease, where T cells damage or destroy vital organs. In order to develop rational, specific methods for treating and preventing these diseases, it is necessary to identify and understand the genetic and biochemical mechanisms that normally control T cell cell responses to self components, and how inherited defects lead these mechanisms to break down. The project focuses on defining how CD4 T cell regulation breaks down in two well established examples of inherited susceptibility to autoimmune disease. The direct action of autoimmune susceptibility genes will be determined at the level of the specific T cells responsible for autoimmune attack and in terms of the biochemical pathways within T cells that are dysregulated. By identifying the mechanisms and biochemical pathways that are dysregulated in autoimmune disorders, the results of this project will reveal targets for understanding and diagnosing autoimmune diseases and for developing new drugs or or vaccines to prevent T cells damaging vital organs and cure these diseases.Read moreRead less
The Role Of Interleukin-21 In The Pathogenesis Of Autoimmune Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$489,060.00
Summary
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 clear viruses and bacteria from the body. However, our studies show that IL-21 also generates T cells that destroy beta cells and cause diabetes. IL-21 is produced at abnormally high levels in an important murine model of spontaneous type-1 diabetes (T1D) and if we block IL-21 we prevent diabetes. This projects' aims assess IL-21 as therapeutic target for T1D.