We seek to gain a detailed understanding of how interactions between the West Nile virus proteins and host factors involved in the IFN response determine the outcome of virus infection. Better understanding of the mechanisms employed by this highly pathogenic virus to disable the mammalian host's IFN response will have wider implications for our understanding of other human diseases such as cancer, autoimmunity and provide new avenues for design of efficient antiviral and anticancer therapies.
Several members of the Flaviviridae family are major pathogens of humans including dengue (DEN), yellow fever (YF), tick-borne encephalitis (TBE), Murray valley encephalitis (MVE), Japanese encephalitis (JE), and hepatitis C virus (HCV). An Australian flavivirus Kunjin (KUN), however, appears to be naturally attenuated and does not cause an overt disease in humans. In contrast, genetically and antigenically closely related to KUN, New York strain of West Nile virus (NY WN) has already caused ~50 ....Several members of the Flaviviridae family are major pathogens of humans including dengue (DEN), yellow fever (YF), tick-borne encephalitis (TBE), Murray valley encephalitis (MVE), Japanese encephalitis (JE), and hepatitis C virus (HCV). An Australian flavivirus Kunjin (KUN), however, appears to be naturally attenuated and does not cause an overt disease in humans. In contrast, genetically and antigenically closely related to KUN, New York strain of West Nile virus (NY WN) has already caused ~500 deaths and over 20,000 registered infections since its emergence in North America in 1999, including 223 deaths and 9122 infections in 2003 alone. Recent studies with DEN indicated that flaviviruses may interfere with early steps of IFN-signalling pathway. The type I Interferon (IFN) response is the first line of defence against viral infections and many viruses have developed different strategies to counteract this response in order to ensure their survival in the infected host. In this grant we seek to exploit our extensive understanding of the molecular biology of KUN virus and the contrasting behaviour of KUN and NY WN viruses to gain an understanding of the role of flavivirus-mediated suppression of host anti-viral IFN response in virus-host relationships and its importance in determining virus virulence.Read moreRead less
Viral Factors Involved In Flavivirus Replication And Virus-host Interactions
Funder
National Health and Medical Research Council
Funding Amount
$743,696.00
Summary
With our increased understanding of virus-host interactions it has become apparent that small, non-structural proteins and small RNAs of most viruses are vital for numerous, often multiple, functions in the viral life cycle. In the proposed project, we seek to gain a detailed understanding of the functions of small nonstructural protein NS2A and small abundant viral RNAs of medicaly important encephalitic flaviviruses, which have remained so far elusive and are at the cutting-edge in the researc ....With our increased understanding of virus-host interactions it has become apparent that small, non-structural proteins and small RNAs of most viruses are vital for numerous, often multiple, functions in the viral life cycle. In the proposed project, we seek to gain a detailed understanding of the functions of small nonstructural protein NS2A and small abundant viral RNAs of medicaly important encephalitic flaviviruses, which have remained so far elusive and are at the cutting-edge in the research field. We anticipate that with a better understanding of the roles of these factors in flaviviral replication and pathogenesis, novel targets for antiviral therapies and-or molecular determinants for inclusion in candidate vaccines will be identified.Read moreRead less
Functions Of Viral Chemokine Receptor Homologues Important For Cytomegalovirus Pathogenesis And Latency
Funder
National Health and Medical Research Council
Funding Amount
$461,597.00
Summary
Cytomegalovirus (CMV) causes life-threatening disease in babies, transplant recipients and HIV-AIDS patients. We will focus on a CMV gene that has been 'hijacked' from the host cell and enables the virus to switch on signalling molecules within infected cells. We will determine how these signals enable CMV to infect sites of the body that are critical for virus transmission and contribute to long-term virus persistence. Our results will provide new strategies for drugs against CMV.
Structure And Function Of The Hepatitis C Virus Glycoproteins E1 And E2.
Funder
National Health and Medical Research Council
Funding Amount
$533,828.00
Summary
Hepatitis C virus (HCV) infects approximately 3 % of the global human population with 150,000-200,000 HCV-infected individuals currently living in Australia. Chronic HCV infection is associated with recurrent, progressively worsening liver disease, liver cirrhosis and hepatocellular carcinoma. The current therapy (interferon-ribavirin) is effective in only 40 % of patients and is often associated with severe side-effects. The mechanisms that HCV uses to replicate in liver cells is poorly underst ....Hepatitis C virus (HCV) infects approximately 3 % of the global human population with 150,000-200,000 HCV-infected individuals currently living in Australia. Chronic HCV infection is associated with recurrent, progressively worsening liver disease, liver cirrhosis and hepatocellular carcinoma. The current therapy (interferon-ribavirin) is effective in only 40 % of patients and is often associated with severe side-effects. The mechanisms that HCV uses to replicate in liver cells is poorly understood. In this project we aim to better understand how the viral glycoproteins, E1 and E2, function in the initiation of infection. In particular, we will examine how these glycoproteins bind to liver cell receptors and then mediate virus-cell membrane fusion. These processes lead to the penetration of the HCV genetic material into the cell where it is replicated. These studies are essential for the discovery of new targets for antiviral agents and vaccines.Read moreRead less
Coordinated Cleavages In The Flavivirus Structural Polyprotein: Role In Virus Assembly And Host-pathogen Interaction
Funder
National Health and Medical Research Council
Funding Amount
$285,000.00
Summary
Flaviviruses are important human pathogens responsible for epidemics of hemorrhagic fever or encephalitis, world-wide. This project aims to investigate unique aspects in the biology of the flaviviruses with wider cell biological and immunological implications. First, we propose to test a mechanism important for the efficient assembly of virus particles. An understanding of this stage of the virus life-cycle will benefit research applying recombinant DNA technology in order to produce replication ....Flaviviruses are important human pathogens responsible for epidemics of hemorrhagic fever or encephalitis, world-wide. This project aims to investigate unique aspects in the biology of the flaviviruses with wider cell biological and immunological implications. First, we propose to test a mechanism important for the efficient assembly of virus particles. An understanding of this stage of the virus life-cycle will benefit research applying recombinant DNA technology in order to produce replication-incompetent viruses for use in vaccination and gene delivery. Second, we have recently discovered a mechanism for immune-modulation, so far unique to the flaviviruses, which interferes with the immune response important in the destruction of virus-infected cells. This project aims to identify the viral gene products responsible for this phenomenon.Read moreRead less
SERPINB2 IS AN INDUCIBLE HOST FACTOR INVOLVED IN ENHANCING HIV-1 TRANSCRIPTION AND REPLICATION
Funder
National Health and Medical Research Council
Funding Amount
$496,446.00
Summary
SerpinB2 is one of the most abundant proteins made at sites of inflammation. We have shown that HIV-1 infection also induces SerpinB2 and that SerpinB2 then helps the virus to replicate. In this grant we seek to understand how the virus causes this protein to be made and how this protein then increases virus replication. In the human population there are different forms of SerpinB2 and this grant seeks to determine whether these different forms affect HIV-1 replications differently. It may for i ....SerpinB2 is one of the most abundant proteins made at sites of inflammation. We have shown that HIV-1 infection also induces SerpinB2 and that SerpinB2 then helps the virus to replicate. In this grant we seek to understand how the virus causes this protein to be made and how this protein then increases virus replication. In the human population there are different forms of SerpinB2 and this grant seeks to determine whether these different forms affect HIV-1 replications differently. It may for instance be possible that an individual who has a certain form of SerpinB2 may be less susceptable to AIDS following HIV-1 infection.Read moreRead less
Immunopathogenesis Of West Nile Virus Encephalitis - Requirement For Interferon-gamma-dependent Soluble Mediators
Funder
National Health and Medical Research Council
Funding Amount
$250,500.00
Summary
Flaviviruses transmitted by arthropods cause considerable illness and death world-wide by their propensity to cause encephalitis. In August 1999, an outbreak of West Nile virus (WNV) encephalitis occurred in New York for the first time, indicating that these viruses are spreading beyond endemic areas. However, the mechanisms by which these viruses kill people are not at all clear. How the immune system deals with them is controlled by a complex network of interactions involving cells and soluble ....Flaviviruses transmitted by arthropods cause considerable illness and death world-wide by their propensity to cause encephalitis. In August 1999, an outbreak of West Nile virus (WNV) encephalitis occurred in New York for the first time, indicating that these viruses are spreading beyond endemic areas. However, the mechanisms by which these viruses kill people are not at all clear. How the immune system deals with them is controlled by a complex network of interactions involving cells and soluble mediators such as cytokines, chemokines, and nitric oxide, many induced or modulated by the cytokine, inteferon-gamma. Evidence suggests that these agents together influence both the types of cells that are mobilised to eradicate virus and also disease outcomes. Our hypothesis is that the host's own immune system is inadvertently responsible for encephalitis through an over-vigorous attempt to destroy the infecting virus, resulting in damage to the brain. To study WNV encephalitis, we are using a mouse model developed in this laboratory that reproduces the features of human disease. Another strain of these mice has the gene for interferon-gamma (IFN) inactivated or 'knocked out', so they cannot respond in the conventional way to virus infection. This mouse survives WNV infection significantly better than normal mice and becomes immune. Therefore we will compare cellular and soluble mediator responses of these mice during WNV infection to those of normal mice. We will also delete specific cell types making interferon-gamma in normal mice, as well as transfering such cells into knockout mice. Experiments will indicate which cell types are responsible and when particular components cause most damage. Thus, we will better understand how interferon-gamma recruits cells that mediate immune brain damage in this model. By understanding the events that lead to death in encephalitis, it may be possible to prevent or ameliorate them by means of immune intervention.Read moreRead less
I am a molecular virologist studying the events of virus replication and virus-host interactions with the ultimate goal to understand the mechanisms determining viral pathogenesis and develop safe and effective vaccines.
The Genetics Governing The Specificity Of T Cell Receptors For Peptide-MHC
Funder
National Health and Medical Research Council
Funding Amount
$303,828.00
Summary
T lymphocytes play a pivotal role in the immune system by recognising virus-infected tissue through the use of highly specific cell surface receptors. These T cell receptors (TCR) recognise viral peptides (p) presented by MHC molecules on the surface of virus-infected cells. For a TCR to be successfully triggered, it must lock onto an exact 3-dimentional pMHC match. In this way, any given TCR must simultaneously recognise both the viral peptide and the MHC presenting it. Such recognition must be ....T lymphocytes play a pivotal role in the immune system by recognising virus-infected tissue through the use of highly specific cell surface receptors. These T cell receptors (TCR) recognise viral peptides (p) presented by MHC molecules on the surface of virus-infected cells. For a TCR to be successfully triggered, it must lock onto an exact 3-dimentional pMHC match. In this way, any given TCR must simultaneously recognise both the viral peptide and the MHC presenting it. Such recognition must be sensitive and precise since a false positive could result in destruction of healthy tissue. There are a huge variety of TCRs and pMHCs, but there are only a few examples where the precise molecular interactions within the TCR-pMHC complex are known. Surprisingly, these studies have shown very limited consistency in the way the TCRs bind the pMHCs and therefore, the structural rules that underlie why TCRs consistently bind MHC remains a mystery of critical importance to this fundamental feature of the immune system. In this proposal, we will attempt to elucidate the rules of TCR-pMHC engagement. Another question to be addressed in this proposal is: During a viral infection, why are certain TCRs chosen above others that also have the capacity to recognise the same viral peptide? By investigating exactly which feature-s of these receptors predisposes their supremacy, we may be better able to predict the outcome of a pathogen attack and to even one day build our own super receptors. Finally, this proposal will also investigate how natural mutations in TCR genes across the human population affect our individual responses to viruses. Overall, advances in each of these core areas of medical research will aid in the development of new intelligent vaccines and individualised drugs for the treatment of cancer and infectious disease.Read moreRead less