Determining The Role Of DOCK8 In CD4+ T And B Cell Differentiation And Its Implications On Autosomal Recessive Hyper IgE Syndrome (AR-HIES)
Funder
National Health and Medical Research Council
Funding Amount
$512,600.00
Summary
Autosomal recessive hyper IgE (AR-HIES) syndrome due to mutations in DOCK8 is a rare primary immunodeficiency whereby patients present with susceptibility to severe and recurrent viral infections as well as an increased risk of developing cancer, severe food and environmental allergies, and atopic disease characterised by hyper IgE and extreme eosinophilia. This grant will investigate how abnormal DOCK8 function in CD4+ T cells and B cells contributes to disease pathogenesis in AR-HIES patients.
This application proposes to study in detail the main target cell for HIV infection, namely CCR5+ CD4 T lymphocytes. After 30 years of the pandemic, fundamental knowledge of these cells, such as locations in the body, differentiation from other lymphocytes, and survival, is still lacking. These attributes determine whether or not they will be infected by HIV, whether this can be prevented by vaccines or CCR5 blocking drugs, and whether their long-term survival results in an inability to eradicat ....This application proposes to study in detail the main target cell for HIV infection, namely CCR5+ CD4 T lymphocytes. After 30 years of the pandemic, fundamental knowledge of these cells, such as locations in the body, differentiation from other lymphocytes, and survival, is still lacking. These attributes determine whether or not they will be infected by HIV, whether this can be prevented by vaccines or CCR5 blocking drugs, and whether their long-term survival results in an inability to eradicate HIV.Read moreRead less
Using Single-cell Genomics To Resolve Functional Diversification By CD4+ T Cells In Vivo
Funder
National Health and Medical Research Council
Funding Amount
$1,048,096.00
Summary
During immune responses, individual CD4+ T cells multiply and produce hundreds of descendants, with close relatives within a family often developing very different skills. How such differences emerge from one ancestor remains unclear. We use new methods to look at individual CD4+ T cells in unprecedented detail, allowing us to see how close relatives begin to grow apart. Using this, we hope to find novel ways of educating CD4+ T cells to prevent infectious and immune-mediated diseases.
Regulation Of T Follicular Helper Cell Development And Effector Function In Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$419,197.00
Summary
Immune cells mature into distinct populations with specialized functions. One subsets are T follicular helper (TFH) cells which are important for instructing B cells to produce antibodies following infection or vaccination. The means by which TFH cells are generated are unknown. We will determine mechanisms whereby TFH cells are produced and how they function. We hope to design approaches that will modulate the function of TFH cells in cases of immunodeficiencies, autoimmunity or vaccination.
Follicular T Helper Cells: Critical Regulators Of Humoral Immune Responses
Funder
National Health and Medical Research Council
Funding Amount
$272,591.00
Summary
B cells are important cells of the immune system that are responsible for producing antibodies in response to infection with pathogens, such as bacteria or viruses, or following vaccinations. In order for B cells to accomplish this task, they require help from a specialised popualtion of T cells, which are another type of immune cell - these are known as follicular T helper (TFH) cells. Under normal circumstances, T cells and B cells specifically interact with one another within lymphoid tissues ....B cells are important cells of the immune system that are responsible for producing antibodies in response to infection with pathogens, such as bacteria or viruses, or following vaccinations. In order for B cells to accomplish this task, they require help from a specialised popualtion of T cells, which are another type of immune cell - these are known as follicular T helper (TFH) cells. Under normal circumstances, T cells and B cells specifically interact with one another within lymphoid tissues such as tonsils, spleens and lymph nodes - here, they engage in a dialogue, the end result of which is the B cells being instructed to produce the appropriate type of antibodies by T cells. However, if tis process is not regulated, the T cells can deliver too little of too much help - this can result in several different types of diseases of the immune system, such as immunodeficiencies (ie insufficient production of antibodies, resulting in individuals becoming susceptible to infections) or autoimmunity (ie production of inappropriate types of antibodies that can recognise cells of the host, resulting in tissue damage and organ failure). The means by which TFH cells instruct B cells to produce antibodies is not completely understood. This project will seek to determine the mechanism whereby TFH cells carry out this important function by performing detailed examination of them follwoing their removal from tissues such as human tonsils and spleens. In doing so, we hope to design approaches that will allow the function of TFH cells to be improved in cases of immunodeficiencies, or suppressed in situations of autoimmune diseases.Read moreRead less
Population Dynamics Of Tissue-specific Effector And Regulatory CD4+ T Cells
Funder
National Health and Medical Research Council
Funding Amount
$394,250.00
Summary
Survival of white blood cells in the body is an active process and is important for the maintainence of a T cell population which can recognise a wide variety of foreign antigens. At present the fate of T lymphocytes which recognise self antigens is unclear. Knowledge of the survival kinetics of self-reactive T lymphocytes and the mechanism by which they are regulated in the normal individual is crucial to be able to control the development of various diseases, including autoimmune diseases. Fro ....Survival of white blood cells in the body is an active process and is important for the maintainence of a T cell population which can recognise a wide variety of foreign antigens. At present the fate of T lymphocytes which recognise self antigens is unclear. Knowledge of the survival kinetics of self-reactive T lymphocytes and the mechanism by which they are regulated in the normal individual is crucial to be able to control the development of various diseases, including autoimmune diseases. From our previous studies of autoimmune gastritis we have generated cell lines of lymphocytes that recognise stomach-specific antigens and with these unique reagents we will perform experiments to determine the fate of these self-reactive T cells in a normal individual. Also we will determine the impact of different amounts of the tissue antigens on the survival and activation of self-reactive T cells, and finally how a special class of lymphocytes, know as regulatory lymphocytes, act in vivo to control the activity of self-reactive T cells. We will use not only classical immunological approaches to address these issues but also state of the art imaging, to visualise the nature of the cell interactions in living tissues. The information arising from this work will underpin strategies to selectively turn off self-reactive lymphocytes that cause disease, will form the basis of clinical development of cell based therapies to treat autoimmune diseases, and the imaging technologies developed in this grant will have wide applicability to the study of a range of immune responses.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
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