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
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.