Determinant Spreading And The Role Of The MHC Class II Region In Systemic And Organ-specific Autoimmunity
Funder
National Health and Medical Research Council
Funding Amount
$140,570.00
Summary
Autoimmune diseases are among the most important group of disorders affecting the adult population. In these diseases the immune system damages organs and tissues producing widespread pathology (systemic autoimmunity such as Lupus erythematosus) or localised disease (organ-specific autoimmunity such as insulin dependent diabetes). We understand very little about how and why the immune system attacks the body's own tissues. This study examines how antibodies and T lymphocytes are formed against c ....Autoimmune diseases are among the most important group of disorders affecting the adult population. In these diseases the immune system damages organs and tissues producing widespread pathology (systemic autoimmunity such as Lupus erythematosus) or localised disease (organ-specific autoimmunity such as insulin dependent diabetes). We understand very little about how and why the immune system attacks the body's own tissues. This study examines how antibodies and T lymphocytes are formed against components located inside cells of the body. The study involves genetically modifying mice by introducing key human genes which influence the development of autoimmunity. In this way the role of these human genes can be examined experimentally without having to work exclusively on patients. We also hope that these mice might be important in creating new models of celiac disease and insulin dependent diabetes. The proposed experiments should tell us how these genes contribute to the development of autoimmune disease. This understanding could be relevant devising treatments and interventions to prevent autoimmune diseases.Read moreRead less
The Structural Basis For Recognition Of HLA-E By Both Innate And Adaptive Immune Systems.
Funder
National Health and Medical Research Council
Funding Amount
$206,255.00
Summary
Biochemistry and structural biology can be used to understand and visualize the three dimesional shape of molecules and the way they interact with other molecules. We will use these approaches to understand how various cells of the immune system recognise the protein HLA-E. This protein is normally present on the surface of healthy cells while it frequently retained inside both tumours and cells infected with viruses. This acts a signal for the immune system to kill these cells. However to avoid ....Biochemistry and structural biology can be used to understand and visualize the three dimesional shape of molecules and the way they interact with other molecules. We will use these approaches to understand how various cells of the immune system recognise the protein HLA-E. This protein is normally present on the surface of healthy cells while it frequently retained inside both tumours and cells infected with viruses. This acts a signal for the immune system to kill these cells. However to avoid being recognized by the immune system some viruses have developed ways to maintain HLA-E expression. This grant will attempt to understand exactly how the immune sytem recognizes HLA-E and how it discriminates between HLA-Eexpressed by healthy cells compared with HLA-E expressed by a virus-infected cell.Read moreRead less
Characterisation Of Susceptibility To Abacavir Hypersensitivity Carried On The HLA-B-5701, -DRB*07 And -DQ3 Haplotype
Funder
National Health and Medical Research Council
Funding Amount
$545,250.00
Summary
Drug hypersensitivity reactions (HSR) are a significant iatrogenic cause of morbidity, and even of mortality. Unfortunately the underlying mechanisms are poorly understood, making it difficult to predict which individuals may be at risk of these reactions. Research indicates that the interaction between specific drugs and the host immune system in HSR is similar to that observed in transplantation and that the major histocompatibility complex (MHC) region of the human genome assumes importance i ....Drug hypersensitivity reactions (HSR) are a significant iatrogenic cause of morbidity, and even of mortality. Unfortunately the underlying mechanisms are poorly understood, making it difficult to predict which individuals may be at risk of these reactions. Research indicates that the interaction between specific drugs and the host immune system in HSR is similar to that observed in transplantation and that the major histocompatibility complex (MHC) region of the human genome assumes importance in this setting, as it does in determining if a transplanted organ is 'rejected' or 'accepted'. We have identified a striking association between MHC genetic markers (HLA-B*5701, -DRB1*0701, and -DQ3) and HSR to the HIV drug abacavir. Carriage of these markers was found in 72% (13-18) of individuals with this reaction, and 0% (0-185) of those who tolerated abacavir (odds ratio 822), thus predicting HSR in 100% of cases, and abacavir tolerance in 97%. This represents one of the most powerful MHC gene associations with a clinical syndrome yet described. As abacavir HSR affects ~5% of abacavir users, knowledge of these genetic factors would be predicted to significantly reduce the risk of susceptible individuals developing HSR, without inappropriately denying access to abacavir. This association between the MHC and abacavir HSR in the clinical setting provides a unique opportunity to characterise mechanisms that underlie this HSR, which may give insights into drug HSR generally. Continued support of this research in the public domain, rather than in the commercial sector, will ensure that commercial considerations do not restrict the dissemination of these findings. Given the high predictive value of this readily performed genetic test in identifying at-risk individuals, there is also a clinical imperative to rapidly identify the gene(s) involved, to provide the most targeted risk assessment possible.Read moreRead less
HLA-E, a protein expressed by all cells regulates both innate and adaptive immune responses by binding to receptors found on white blood cells. This project will examine different ways that lymphocytes recognise this protein and its role in infection and transplantation.
Major Xenoantigens For Neovascularised Porcine Xenografts: The Role Of PERV And MHC In Rejection And Tolerance
Funder
National Health and Medical Research Council
Funding Amount
$504,750.00
Summary
Cross-species transplants (xenografts) of pig organs which use donor pig blood vessels are rejected by antibody which recognises a special target (xenoantigen) on the pig blood vessels; other pig tissue transplants (cellular transplants) which use recipient (not donor pig) blood vessels, are rejected by white blood cells called CD4 T cells. The pig targets recognised by the xenoreactive CD4 T cells are unknown. We plan to identify the major target(s) involved in cellular xenograft rejection. Thi ....Cross-species transplants (xenografts) of pig organs which use donor pig blood vessels are rejected by antibody which recognises a special target (xenoantigen) on the pig blood vessels; other pig tissue transplants (cellular transplants) which use recipient (not donor pig) blood vessels, are rejected by white blood cells called CD4 T cells. The pig targets recognised by the xenoreactive CD4 T cells are unknown. We plan to identify the major target(s) involved in cellular xenograft rejection. This information can then be used to specifically remove or disable only those CD4 T cells capable of recognising the pig tissue and hence facilitate xenograft survival or tolerance without immunosuppression. In this way, the remainder of the CD4 T cell population and immune system is preserved intact. Recent studies have demonstrated that a pig virus (PERV) can be transmitted from pig tissue xenografts to recipient tissues. Our studies have also suggested that the process of xenograft rejection and the immunological recognition of transplant recipient cells infected with the pig virus, are closely related. We plan to investigate this relationship and ascertain whether the immunological destruction of the pig tissue xenograft is largely due to an immune response generated against the pig virus(es) it carries. As an extension of this concept, we will investigate whether long-term xenograft survival (tolerance) is associated with lack of immune reactivity to the pig virus and hence a continual capacity for pig virus to be transmitted to host tissues. This outcome could result in the development of unwanted disease(s) in transplant patients. To prevent these problems, our studies will determine whether it will be essential for such pig virus to be eliminated from the donor pig tissue before transplantation, e.g. by the development of potent anti-viral agents and-or via the development of pig herds that have been genetically engineered to be pig virus (PERV)-deficient.Read moreRead less
Antigen Selection In The MHC-restricted Cellular Immune Response
Funder
National Health and Medical Research Council
Funding Amount
$175,570.00
Summary
The body's white cells eliminate microorganisms through the actions of immune lymphocytes and other cells which conspire to kill and neutralise these unwanted guests. When microorganisms hide inside the cells of the body they are still detected by a set of T lymphocytes which have specific receptors for scrutinising the surface of cells for any changes which might signal an intracellular infection. The immune system is ever vigilant in its search for signs of infection which are generally appare ....The body's white cells eliminate microorganisms through the actions of immune lymphocytes and other cells which conspire to kill and neutralise these unwanted guests. When microorganisms hide inside the cells of the body they are still detected by a set of T lymphocytes which have specific receptors for scrutinising the surface of cells for any changes which might signal an intracellular infection. The immune system is ever vigilant in its search for signs of infection which are generally apparent when molecules called antigens are released by microorganisms and captured by the body's cells. This activates lymphocytes resulting in an immune response capable of eliminating the microorganisms. Scrutiny of the body's cells by lymphocytes occurs continuously even when there is no infection present in the body. Following infection of a cell, microbial antigens reveal the infection by their appearance on the cell surface where they are detected by the immune system's lymphocytes. This occurs through a mechanism called antigen presentation. During antigen presentation the proteins inside the cell, including those of any invading microorganism, are first degraded into shorter molecules called peptides. This event is called antigen processing. A fraction of the peptides created by antigen processing are captured by specialised receptors present on all cells. These receptors are called HLA or histocompatibility molecules. This project examines the molecular events which mediate the capture of peptide antigens by HLA molecules. The main focus is on those peptide antigens which elicit killer T cell responses by the immune system. A knowledge of how these peptides are selected for presentation and how they are captured and carried to the cell surface is fundamental to understanding immune responses to microorganisms, tumours, allergens, transplants and self tissues as in autoimmunity. Therefore the study is of great general relevance.Read moreRead less
Macrophages are white blood cells that provide front line defence against infection by initiating inflammatory responses by ingesting or phagocytosing microbes and by releasing soluble messengers (cytokines) to recruit other immune cells. These defensive functions require extensive trafficking of proteins within the macrophages. Protein trafficking is orchestrated in part by a family of membrane fusion proteins called SNAREs. By defining the relevant SNAREs, we have recently discovered a much ac ....Macrophages are white blood cells that provide front line defence against infection by initiating inflammatory responses by ingesting or phagocytosing microbes and by releasing soluble messengers (cytokines) to recruit other immune cells. These defensive functions require extensive trafficking of proteins within the macrophages. Protein trafficking is orchestrated in part by a family of membrane fusion proteins called SNAREs. By defining the relevant SNAREs, we have recently discovered a much acclaimed and novel pathway that allows efficient, combined cytokine secretion and phagocytosis in macrophages. Our studies proposed here will now expand on this discovery by comparing the phagocytic process, in terms of SNARE-mediated membrane and cytokine trafficking, for a wide range of microbes, highlighting differences that could provide new avenues for drug development. Moreover, since our strategy of using SNAREs to investigate and map trafficking pathways has proven so successful, we will now launch a major large-scale initiative to study ALL SNARE-mediated trafficking pathways in macrophages using a discovery pipeline of assays, including live cell imaging, we have developed. This will provide valuable information on many SNAREs including those associated with disease, and will elucidate trafficking pathways governing all macrophage actions in immunity, including cytokine secretion and antigen presentation. All of these pathways are highly relevant to current drug targets being used clinically or studied in inflammatory disease and for the development of vaccines.Read moreRead less
A Structural Investigation Into The Adaptive Immune Response To A Persistent And Ubiquitous Human Virus
Funder
National Health and Medical Research Council
Funding Amount
$574,890.00
Summary
This proposal is focussed on understanding the precise shape of proteins that control the immune response to Epstein Barr Virus. EBV is an ubiquitous human pathogen that has been linked to a number of cancers. This research proposal will further our understanding of the immune response to EBV, which will lay the foundations for developing therapeutics against this disease.
Fine Mapping And Characterisation Of Polymorphic Immunoregulatory Genes In The Central MHC
Funder
National Health and Medical Research Council
Funding Amount
$529,656.00
Summary
The major histocompatibility complex (MHC) is a group of genes that is usually inherited as a block. The group includes the HLA genes which can serve as markers for neighbouring genes that are less well characterised. For example, some variant forms (polymorphisms) of the HLA genes mark differences in susceptibility to diabetes, lupus and IgA deficiency. We propose that this may be caused by variations in the neighbouring uncharacterised genes affecting control of persistent inflammation of vari ....The major histocompatibility complex (MHC) is a group of genes that is usually inherited as a block. The group includes the HLA genes which can serve as markers for neighbouring genes that are less well characterised. For example, some variant forms (polymorphisms) of the HLA genes mark differences in susceptibility to diabetes, lupus and IgA deficiency. We propose that this may be caused by variations in the neighbouring uncharacterised genes affecting control of persistent inflammation of various target organs. Evidence so far suggests a gene in the central MHC may be responsible. In this project we will study DNA from patients who have unusual combinations of HLA and other MHC genes, to further define which part of the MHC contains the critical immunoregulatory genes. Most genes in the MHC have now been identified by the Human Genome Project, so we will be able to select the most promising candidates in the region of interest. We will then use DNA of known HLA types to determine if the candidate genes vary between individuals. The function of interesting genes will then be investigated by creating cell lines carrying part of the gene in the reverse (anti-sense) orientation. This generates a reverse messenger (m) RNA which binds the normal mRNA and prevents synthesis of the protein. We will then examine which responses of the resultant cell lines are abnormal (eg: production of inflammatory mediators or cytokines). Having elucidated the functions our genes, we will overexpress each version that occurs in patients in cultured cells and look for differences in function. In parallel with this work, we will use laboratory mice with known combinations of MHC genes to establish the effects of particular genes in a live animal.Read moreRead less