Molecular Interactions Of The Tetraspanins CD37, TSSC6 And CD151 In T Cells
Funder
National Health and Medical Research Council
Funding Amount
$566,575.00
Summary
The tetraspanins are a new type of protein that are found at the surface of cells. Cells of the immune system, such as white blood cells, display at their surface, up to 20 different tetraspanin proteins. However, the precise contributions of these tetraspanin proteins to immunity is still not clear, nor is it clear exactly how tetraspanin proteins differ from one another and why white blood cells need to display so many different tetraspanins. Using genetic technology we have created mice which ....The tetraspanins are a new type of protein that are found at the surface of cells. Cells of the immune system, such as white blood cells, display at their surface, up to 20 different tetraspanin proteins. However, the precise contributions of these tetraspanin proteins to immunity is still not clear, nor is it clear exactly how tetraspanin proteins differ from one another and why white blood cells need to display so many different tetraspanins. Using genetic technology we have created mice which are unable to express certain individual tetraspanin proteins at their cell surface. Excitingly, the immune systems of these mice are not normal, in particular one type of white blood cell, the T cell responds in an exaggerated manner to stimulation. These results suggest a role for tetraspanins in the control and regulation of the immune system. This project will extend these results and work out the precise molecular mechanism by which the tetraspanins exert this control. In the future, a full understanding of how tetraspanins control T cells may ultimately lead to novel ways of controlling the immune system.Read moreRead less
Dendritic cells are a very rare type of white blood cell which play a critical role in the initiation of the immune response. They are of particular interest to scientists interested in vaccination, as for a vaccine to work effectively, the vaccine must be presented to the rest of the immune system by the dendritic cell. It has only recently become apparent that there are several types of dendritic cell, and these different types of dendritic cell vary in their ability to present a vaccine to th ....Dendritic cells are a very rare type of white blood cell which play a critical role in the initiation of the immune response. They are of particular interest to scientists interested in vaccination, as for a vaccine to work effectively, the vaccine must be presented to the rest of the immune system by the dendritic cell. It has only recently become apparent that there are several types of dendritic cell, and these different types of dendritic cell vary in their ability to present a vaccine to the immune system. We have already identified some proteins that are expressed on the surface of only one type of dendritic cell. We will explore the possible use of these proteins as a means of delivering a vaccine to only one type of dendritic cell. This project will also identify new genes that are expressed in some types of dendritic cells but not others. These new genes whose expression does differ amongst the dendritic cells are potential targets for manipulating the immune system and ensuring more efficient vaccination.Read moreRead less
Co-administration Of DNA Encoding Co-stimulatory Molecules Enhances The Efficacy Of Immune Response To Foreign Antigen
Funder
National Health and Medical Research Council
Funding Amount
$182,000.00
Summary
Vaccines to prevent or treat infectious diseases and some cancers are urgently needed. Infected cells and some cancer cells display unique proteins which the body's immune system can recognises as 'foreign'. The body will then mount an immune response, which, if successful, will eradicate the infected or cancerous cells. Dendritic cells (DCs) initiate the body's immune response by instructing other immune cells to mount a response. For a vaccine to be successful it is important that the vaccine ....Vaccines to prevent or treat infectious diseases and some cancers are urgently needed. Infected cells and some cancer cells display unique proteins which the body's immune system can recognises as 'foreign'. The body will then mount an immune response, which, if successful, will eradicate the infected or cancerous cells. Dendritic cells (DCs) initiate the body's immune response by instructing other immune cells to mount a response. For a vaccine to be successful it is important that the vaccine activates the DCs in the right way. We propose to activate DCs by vaccinating with DNA encoding recently identified costimulatory molecules, as well as DNA encoding the foreign antigen. Our earlier work leads us to believe that this will enhance the immune response, and lead to a more effective state of immunityRead moreRead less
Polarized Trafficking Of E-cadherin In Epithelial Cells.
Funder
National Health and Medical Research Council
Funding Amount
$515,564.00
Summary
The cell adhesion protein E-cadherin is expressed in all epithelial tissues of the body where it has essential functions during development and in the adult in establishing and maintaining polarized cell monolayers. E-cadherin is also a vital tumour suppressor, its normal function guarantees that cells or even early tumours cannot metastasise; in contrast E-cadherin is always lost or malfunctions in malignant tumours. Earlier studies showed that E-cadherin is constantly moved, or trafficked, to ....The cell adhesion protein E-cadherin is expressed in all epithelial tissues of the body where it has essential functions during development and in the adult in establishing and maintaining polarized cell monolayers. E-cadherin is also a vital tumour suppressor, its normal function guarantees that cells or even early tumours cannot metastasise; in contrast E-cadherin is always lost or malfunctions in malignant tumours. Earlier studies showed that E-cadherin is constantly moved, or trafficked, to and from the surface of epithelial cells. This trafficking has dual roles, firstly in delivering newly-made E-cadherin to the surface where it functions and secondly, in regulating its adhesive function. Our research in this project is focussed on the molecules and intracellular compartments that control the delivery of E-cadherin to the cell surface. E-cadherin must be sorted in order to be delivered to the correct side of the cell. Having previously discovered the sorting signal in E-cadherin, we will now identify the cognate adaptor protein(s) that accomplish this sorting. New imaging techniques allow us to study protein trafficking inside live cells. Such studies have recently revealed that E-cadherin passes through a recycling endosome compartment on its way to the cell surface. This unexpected route, and the structure and role of the recycling endosome will now be studied in detail in live cells. Finally we will compare the sorting and trafficking of E-cadherin with the closely-related N-cadherin protein, to determine whether there are inherent differences in their trafficking that could explain their opposite roles in tumour cells, where N-cadherin is substituted for E-cadherin and allows metastatic behaviour. These studies will provide important information for understanding the adhesive and tumour suppressive roles of E-cadherin. In addition our findings will generate information fundamental to our understanding of cell polarity and protein sorting.Read moreRead less
The Interaction Between CD46 And PSD-95/Dlg-4: Roles In Cell Polarisation And CD46 Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$70,000.00
Summary
Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single ....Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single protrusion, or uropod, that forms the basis for cell-cell interactions, (ii) the formation of an immune synapse which allows a T cell to recognise a pathogen, and (iii) the direction of the cellular killing machinery towards the target. The process of cell polarisation is best characterised in neurons and epithelial cells, both of which are asymmetric. In each cell type, a major mechanism of regulating polarisation is the expression and targeting of a family of proteins containing regions called PDZ domains. PDZ domains mediate protein-protein interactions and so allow the assembly of large molecular scaffolds which hold proteins in specific cell sites. The loss of cell polarity in some cells is thought to cause uncontrolled proliferation and tumour progression, and some of the PDZ-containing proteins are tumour suppressors. We have identified a PDZ-containing protein that is polarised in T cells, and have evidence that this protein interacts with and controls the polarisation of a cell surface receptor whose functions include the regulation of T cell function and proliferation. The aim of this proposal is to determine the mechanisms and functional consequences of polarisation of these two proteins in T cells, and to determine whether their interaction or polarisation is important for T cell proliferation.Read moreRead less
Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single ....Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single protrusion, or uropod, that forms the basis for cell-cell interactions, (ii) the formation of an immune synapse which allows a T cell to recognise a pathogen, and (iii) the direction of the cellular killing machinery towards the target. The process of cell polarisation is best characterised in neurons and epithelial cells, both of which are asymmetric. In each cell type, a major mechanism of regulating polarisation is the expression and targeting of a family of proteins containing regions called PDZ domains. PDZ domains mediate protein-protein interactions and so allow the assembly of large molecular scaffolds which hold proteins in specific cell sites. The loss of cell polarity in some cells is thought to cause uncontrolled proliferation and tumour progression, and some of the PDZ-containing proteins are tumour suppressors. We have identified a PDZ-containing protein that is polarised in T cells, and have evidence that this protein interacts with and controls the polarisation of a cell surface receptor whose functions include the regulation of T cell function and proliferation. The aim of this proposal is to determine the mechanisms and functional consequences of polarisation of these two proteins in T cells, and to determine whether their interaction or polarisation is important for T cell proliferation.Read moreRead less
PrtFII, A Streptococcus Pyogenes Fibronectin Binding Protein, And Invasive Diseases.
Funder
National Health and Medical Research Council
Funding Amount
$296,540.00
Summary
Our recent work revealed that, in the Aboriginal population, young age is a risk factor for severe invasive diseases caused by group A streptococcus. For group A streptococcus infection to occur, bacterial attachment is the first step. The bacterium attaches to host cells through interactions involving host fibronectin and the pathogen's fibronectin-binding proteins. We have found that streptococcal strains from severe disease cases are more likely to have the gene for PrtFII, a fibronectin bind ....Our recent work revealed that, in the Aboriginal population, young age is a risk factor for severe invasive diseases caused by group A streptococcus. For group A streptococcus infection to occur, bacterial attachment is the first step. The bacterium attaches to host cells through interactions involving host fibronectin and the pathogen's fibronectin-binding proteins. We have found that streptococcal strains from severe disease cases are more likely to have the gene for PrtFII, a fibronectin binding protein, than those from uncomplicated skin sores. In this application we propose to extend this observation and compare biochemical properties of PrtFII from strains belonging to the above two sets of collections. We hypothesise that PrtFII from invasive strains bind to fibronectin more tightly than the proteins from strains that cause uncomplicated infection. We also will test whether sera from invasive disease cases have lower titre of antibodies to the conserved region of PrtFII than sera from uncomplicated cases. A streptococcal vaccine by necessity has to be a multi-component vaccine to cover a wide spectrum of diseases and epidemiological differences. The study proposed here may provide a basis to argue whether or not to include PrtFII in such a multi-component vaccine.Read moreRead less
The Role Of The Interaction Of The CMV M11 Immune Evasion Molecule With CD44 In Viral Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$457,500.00
Summary
Herpesviruses can cause infections that persist for the lifetime of the host. They have evolved many mechanisms to elude the host's immune response that would otherwise eliminate them. One memberof the herpesvirus family that is particularly adept at avoiding host immunity is cytomegalovirus. This virus, while not causing symptoms in healthy individuals, is a significant cause of disease and mortality in individuals with suppressed immune systems such as transplant and AIDS patients, and in the ....Herpesviruses can cause infections that persist for the lifetime of the host. They have evolved many mechanisms to elude the host's immune response that would otherwise eliminate them. One memberof the herpesvirus family that is particularly adept at avoiding host immunity is cytomegalovirus. This virus, while not causing symptoms in healthy individuals, is a significant cause of disease and mortality in individuals with suppressed immune systems such as transplant and AIDS patients, and in the fetus which has a poorly developed immune system. In the current project we will explore at a molecular level how a virus-encoded molecule called m11 interferes with the functions of a cellular receptor called CD44 that has a range of cell functions including cell migration, activation and proliferation and signal transduction. The interaction of m11 with CD44 modifies cell migration and is likely to affect cell activation. Defining how m11 mediates its affects will allow us to define strategies to develop potential antiviral therapies. As CD44 is also involed in contributing to a range of diseases where inappropriate inflammation develops it may be that m11, or derivatives of it, could be harnessed to ameliorate these inflammatory diseases.Read moreRead less