The Transcription Factors C-Rel And RelA Serve Distinct Roles In The Devlopment And Function Of CD4 Regulatory T Cells
Funder
National Health and Medical Research Council
Funding Amount
$492,991.00
Summary
An unfortunate consequence of immune function is that occasionally rogue immune cells are produced that attack the host and lead to the development of so-called autoimmune diseases such as arthritis. Normally a white blood cell called a regulatory T cell suppresses these self reactive immune cells. We have identified factors that govern genetic programs in regulatory T cells. Understanding how these factors work should permit the development of new strategies to combat autoimmune diseases.
The Function Of Transcription Factor SCL In T Cell Development.
Funder
National Health and Medical Research Council
Funding Amount
$504,750.00
Summary
SCL is a gene which is abnormally expressed in a large percentage of human T cell leukaemias. Mouse models that increase SCL levels have demonstrated that T cell maturation is abnormally affected by SCL. Thus, providing a clue as to how T cell leukemias arise. By utilising recombinant DNA technology we are now able to control SCL levels in T cell maturation. We can either increase the level of SCL using pharmacological reagents or we can genetically remove SCL from maturing T cells. This double- ....SCL is a gene which is abnormally expressed in a large percentage of human T cell leukaemias. Mouse models that increase SCL levels have demonstrated that T cell maturation is abnormally affected by SCL. Thus, providing a clue as to how T cell leukemias arise. By utilising recombinant DNA technology we are now able to control SCL levels in T cell maturation. We can either increase the level of SCL using pharmacological reagents or we can genetically remove SCL from maturing T cells. This double-edged approach will allow us to monitor the effects of SCL on maturing T cells with a precision that has never previously been achieved. Results from this approach will provide new insights into how T cell leukaemia develops and provide the foundation for new rational based treatments.Read moreRead less
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
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
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.
Evaluation Of Immune Correlates For Virus-specific CD8+ T Cells Following Prime-boost Vaccination
Funder
National Health and Medical Research Council
Funding Amount
$397,889.00
Summary
This project will use cutting-edge technology to evaluate the quality of virus-specific white blood cells generated following vaccination. Clinically relevant vaccination strategies will be analysed in a well characterised mouse model of infection to produce correlates associated with protective vaccine efficacy, particularly in an immunosupressed setting. This will lead to more focused research and ultimately the development of prophylactic and therapeutic HIV vaccines.
Systematically Exploring The Contribution Of Immunoproteasome To Immunodominance And T Cell Function
Funder
National Health and Medical Research Council
Funding Amount
$499,860.00
Summary
Vaccine will help us to fight both infectious diseases and malignancy. However, there are few successful vaccines for infectious agents and there is simply no vaccine to cure any tumor at the moment. So, it is essential for us to learn the basics related to vaccine development. Killer T cells eliminate tumour cells or virally infected host cells by recognising fragments (epitopes) derived from tumour- or virus-derived proteins displayed on a host molecule called MHC. Normally multiple epitopes a ....Vaccine will help us to fight both infectious diseases and malignancy. However, there are few successful vaccines for infectious agents and there is simply no vaccine to cure any tumor at the moment. So, it is essential for us to learn the basics related to vaccine development. Killer T cells eliminate tumour cells or virally infected host cells by recognising fragments (epitopes) derived from tumour- or virus-derived proteins displayed on a host molecule called MHC. Normally multiple epitopes are generated as part of the protein recycling program referred as proteine degradation which is mainly conducted by bundled enzyme complex, called proteasome. Two major forms of proteasomes are expressed by most cells. One called house-keeping proteasome and the other, which replaces the house-keeping one during viral infections is called immunoproteasome. The role that the immunoproteasome plays during anti-viral and anti-tumoral immune responses is not fully understood. In addition, the immunoproteasome is also expressed by a few cell types that do not suppose to need it if its function is entirely to generate better epitopes for MHC to display. In this project, we will sytematically explore the contribution of the immunoproteasome to overall anti-viral and anti-tumoral immune responses in three mouse model systems. The shared feature of these systems is that multiple killer T cell epitopes have been defined, which could potentially provide us with very sensitive assessments. The three systems are anti-influenza, anti-vaccinia virus and anti-tumor antigen (NY-ESO-1) mouse models.Read moreRead less
Regulation Of Epithelial Migration By Scribble In Development And Wound Repair
Funder
National Health and Medical Research Council
Funding Amount
$516,078.00
Summary
The movement of epithelial cells within our body (the cells that form the thin protective layer on exposed bodily surfaces such as skin and the lining of internal cavities, ducts, and organs) is essential for our normal embryonic development as well as for healing of wounds following injury. Understanding how this movement is regulated is therefore a fundamental area of medical biology. Although much is known about the mechanics of how a cell moves, the signals used to coordinate this movement s ....The movement of epithelial cells within our body (the cells that form the thin protective layer on exposed bodily surfaces such as skin and the lining of internal cavities, ducts, and organs) is essential for our normal embryonic development as well as for healing of wounds following injury. Understanding how this movement is regulated is therefore a fundamental area of medical biology. Although much is known about the mechanics of how a cell moves, the signals used to coordinate this movement so as to ensure that each cell migrates to the right place during embryonic development or in response to a wound is not well understood. A number of lines of evidence suggest that proteins required for the correct orientation of cells within our body (a property of cells known as polarity) may be essential for this process. Mutation of the polarity protein Scribble in the fly, zebrafish and mouse causes a disorganization of epithelial tissues during embryonic development. We have now shown that Scribble is required for cells to orientate correctly so as to be able to move in response to a wound in tissue culture and also during embryonic development and wound healing in the mouse. It is currently unknown how Scribble regulates migration. Here we propose to identify the molecules that Scribble regulates to coordinate cell movement during development and tissue repair. These studies will provide new insights into the fundamental process of how cell movement is coordinated and could lead to novel strategies for improved treatment of tissue injuries.Read moreRead less