Induction Of Natural T-Regulatory Cells By Thymic Dendritic Cell Populations
Funder
National Health and Medical Research Council
Funding Amount
$413,775.00
Summary
In this study, we will determine the roles of the antigen presenting cells, namely denderitic cells, in the induction of T-regulatory cell (T-reg) developemnt in the thymus. T-reg cells play important roles in controlling the development of autoimmunity. This study will help to understand the possible causes of autoimmune diseases and to develop new treatments for these diseases.
The Role Of C-Cbl In The Regulation Of T Cell Signalling And Development
Funder
National Health and Medical Research Council
Funding Amount
$527,250.00
Summary
c-Cbl is a member of a multi-adaptor protein family that can interact with many signalling proteins via its different domains. Cbl proteins have been implicated as negative regulators of signalling pathways involving protein tyrosine kinases (PTKs). PTKs are enzymes which add phosphate groups to tyrosine residues on other protein substrates, and the process of tyrosine phosphorylation acts as a potent biochemical switch to turn signalling cascades on and off. Studies of Cbl-deficient (knockout) ....c-Cbl is a member of a multi-adaptor protein family that can interact with many signalling proteins via its different domains. Cbl proteins have been implicated as negative regulators of signalling pathways involving protein tyrosine kinases (PTKs). PTKs are enzymes which add phosphate groups to tyrosine residues on other protein substrates, and the process of tyrosine phosphorylation acts as a potent biochemical switch to turn signalling cascades on and off. Studies of Cbl-deficient (knockout) mice show that Cbl proteins are important in regulating the development of, and signalling by, cells of the immune system called T cells. c-Cbl knockout mice show greatly enhanced PTK-signalling responses and deregulated activity of a PTK called ZAP-70. The mechanism of this is not known, but analysis of a c-Cbl mutant mouse shows that this is not dependent on the tyrosine kinase binding (TKB) domain of c-Cbl. Therefore other functional domains of Cbl must be responsible for the increased signalling response in the c-Cbl knockout mouse. One candidate is the highly conserved RING finger domain which can modify Cbl-associated PTKs by addition of ubiquitin molecules. Ubiquitination of a protein often, but not always, leads to its degradation, and this could be how Cbl controls the strength and duration of signalling in T cells. However there may be other functions of the conserved RING finger yet to be identified. c-Cbl itself is prominently and very rapidly modified by tyrosine phosphorylation on tyrosine 737 by the Fyn PTK following T cell activation, but the role of this modification is not known and could also be essential for c-Cbl s function in T cells. We plan to investigate the roles of the RING finger domain and Fyn-mediated tyrosine phosphorylation in c-Cbl regulation of T cell signalling by analyzing knock-in mice that carry specific mutations disrupting the RING finger or tyrosine 737 in the c-Cbl gene.Read moreRead less
Co-ordinating The Intrinsic And Extrinsic Arms Of Hematopoiesis
Funder
National Health and Medical Research Council
Funding Amount
$615,286.00
Summary
The cell types of the blood, such as red and white blood cells, are produced in the bone marrow from a rare stem cell. The stem cell uses a handfull of important master-regulatory genes that act in a hierarchy to promote the blood cell differentiation process. This research aims to understand how these master-regulators function in isolation and together in producing the white blood cells that are required for our immune response to microbes, vaccination and to prevent cancer.
Discovery Of Novel T Cell Oncogenes By Using A Functional Retroviral CDNA Library Screen.
Funder
National Health and Medical Research Council
Funding Amount
$692,470.00
Summary
T cells mature in an organ called the thymus which is located on top of the heart. Blood borne T cell precursors enter the thymus after being resident in the bone marrow. T cell leukaemia is a disease where a blood cell that is committed to becoming a T cell is blocked from maturing into a functional cell. Instead, the leukaemic immature T cell uncontrollably divides to make endless non-functional copies of itself. As a result, normal functional T cells are outcompteted and the immune system is ....T cells mature in an organ called the thymus which is located on top of the heart. Blood borne T cell precursors enter the thymus after being resident in the bone marrow. T cell leukaemia is a disease where a blood cell that is committed to becoming a T cell is blocked from maturing into a functional cell. Instead, the leukaemic immature T cell uncontrollably divides to make endless non-functional copies of itself. As a result, normal functional T cells are outcompteted and the immune system is crippled. Patients generally die due to opportunistic infection. The molecular causes of T cell leukaemia are slowly being discovered. Up to 50% of all human T cell leukaemias overexpress SCL-TAL-1. Other T cell leukaemia-causing genes (oncogenes) include Ras and Notch. Current leukaemia treatments include chemotherapy and bone marrow transplants but even these fail ~30% of the time. Consequently, all T cell oncogenes need to be discovered so that disease-specific treatments can be generated. This proposal will utlise a functional retroviral cDNA library screen to uncover novel T cell lineage commitment genes and T cell oncogenes. This will be accomplished by constructing a coloured [GFP] cDNA library (a library of genes) that will be transfected (inserted) into immature T cells that cannot develop down the T cell pathway owing to the lack of a crucial gene (Rag-1). The T cell oncogene Ras and the T cell lineage commitment gene Notch can move cells past the Rag-1 block. If there is a gene in the cDNA library that can compensate for the lack of Rag-1 and allow the cells to mature we will detect it using high speed flow cytometryic cell sorting (like sieving weevils from flour very quickly). Once we find this cell we will isolate the gene using the colour tag. The potential oncogenes uncovered will provide the foundation for next generation drug development that targets each leukaemia based on its cause.Read moreRead less
Regulation Of B Lymphocyte Survival And Tumourigenesis By The TRAF2-TRAF3-cIAP Signaling Complex
Funder
National Health and Medical Research Council
Funding Amount
$439,395.00
Summary
A major contributing factor in the development of cancer is the loss of the normal controls that regulate cell survival. We have identified a group of proteins that control the survival of B cells, the white blood cells responsible for producing the antibodies that fight infections. In this project we will investigate the mechanisms by which these proteins function and how inactivation of their functions can lead to multiple myeloma, an aggressive cancer of antibody producing cells.
The Role Of The Dendritic Cell Surface Molecule Clec9A In Dendritic Cell Subset Function And Dead Cell Recognition
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
Dendritic cells (DC) are sentinels of the immune system. DC monitor the environment and regulate tolerance to self versus immunity to dangerous material. Different types of DC perform different jobs. We have identified a new surface molecule, Clec9A, on some mouse and human DC. We will investigate the function of Clec9A in the immune response. We will also use Clec9A to help unite mouse and human DC biology, since until now there have been few useful marker molecules common to both species.
Direct Characterisation Of Naive Epitope-specific T Cell Populations And Their Influence On Immune Responses
Funder
National Health and Medical Research Council
Funding Amount
$314,983.00
Summary
CytotoxicT cells (CTLs) recognize and remove virus infected cells. Both the number and the diversity of T cells involved in the response influence viral clearance. We plan to use a novel technology to directly analyze the numbers and diversity of such CTLs in mice prior to infection. This will clarify how characteristics of cell populations prior to infection define the immune response after infection. This is critical for vaccine design to maximize the efficiency of the immune response.
Immune reactions are mediated by the expansion of white blood cells, and the progeny of this expansion is steered down different developmental pathways depending upon the nature of the initial infection or insult. We have recently identified a new means for control of the developmentwhite blood cells, and will here define this mechanism. These studies will open new opportunities for autoimmune therapeutics and vaccine development.
The establishment of an immune system that is able to distinguish between self and non-self is of fundamental importance for good health and survival. How this specificity is achieved has been an area of intense investigation for many years because a breakdown of this process leads to the development of autoimmune diseases, such as diabetes, or an inability to fight pathogenic organisms. It has been known for many years that the development T cells, a subset of cells involved in mounting immune ....The establishment of an immune system that is able to distinguish between self and non-self is of fundamental importance for good health and survival. How this specificity is achieved has been an area of intense investigation for many years because a breakdown of this process leads to the development of autoimmune diseases, such as diabetes, or an inability to fight pathogenic organisms. It has been known for many years that the development T cells, a subset of cells involved in mounting immune responses, occurs in the thymus. The thymus produces large numbers of immature T cells (called thymocytes) from which a small number receive the appropriate signals to survive and develop into mature T cells. These tailor-made T cells can then enter the blood and peripheral lymphoid organs where they fight infectious organisms without reacting against host (i.e. self) tissues. The work for this project is aimed at determining how proteins inside thymocytes transmit signals that determine whether thymocytes either survive, and develop into T cells, or are eliminated because they react too strongly with self proteins. We have established that a protein called c-Cbl is central to this process as it regulates the initial strength of the signal that determines the fate of thymocytes. Our aim is to identify the putative key protein regulated by c-Cbl that can sense when a signal is too strong following the binding of a thymocyte to a self protein and directs a cell death signalling response. From this critical point of signal splitting we also aim to identify proteins that relay the death signal to the nucleus where they trigger the production of well-characterised proteins required to mediate cell death. By identifying the proteins in this signalling pathway we will have a greater capacity to control the magnitude of immune responses and therefore be able to lessen tissue damage caused by autoimmune reactions.Read moreRead less
Identification And Characterisation Of Nessy; A Novel Gene Important For T Cell Differentiation.
Funder
National Health and Medical Research Council
Funding Amount
$250,500.00
Summary
This project aims to identify, and understand the function of, a new gene involved in the immune system. The Nessy mouse strain was developed in Prof. Goodnow s Medical Genome Centre at the Australian National University. It has a mutation in an unknown gene which causes a defect in T lymphocytes- white blood cells which are important for fighting infection. This project has three major aims: 1) to identify the gene. 2) to understand the defects in T lymphocytes caused by the gene. 3) to identif ....This project aims to identify, and understand the function of, a new gene involved in the immune system. The Nessy mouse strain was developed in Prof. Goodnow s Medical Genome Centre at the Australian National University. It has a mutation in an unknown gene which causes a defect in T lymphocytes- white blood cells which are important for fighting infection. This project has three major aims: 1) to identify the gene. 2) to understand the defects in T lymphocytes caused by the gene. 3) to identify which other genes interact with the mutant gene. Thus will allow us to understand how the mutant gene causes the T lymphocyte defects. This project will improve our understanding of the development and functioning of T lymphocytes, which play a central role in the immune system. Since the genomes of mice and humans are very similar, it is likely that we will be able to identify a human counterpart to the Nessy gene.Read moreRead less