Roles Of Virus-integrin Interactions And Rotavirus Modulation Of Host Cell Responses In Viral Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$474,000.00
Summary
Rotaviruses are the main cause of severe gastroenteritis in children, and cause 1 in 27 Australian children under the age of 5 years to spend time in hospital. There is currently no rotavirus vaccine available. We aim to discover how rotavirus interacts with host cells. This information is necessary to formulate a safe and effective vaccine, or a therapeutic agent that can block virus growth in host cells. Previously, we showed that rotavirus attaches to cells and enters them using several membe ....Rotaviruses are the main cause of severe gastroenteritis in children, and cause 1 in 27 Australian children under the age of 5 years to spend time in hospital. There is currently no rotavirus vaccine available. We aim to discover how rotavirus interacts with host cells. This information is necessary to formulate a safe and effective vaccine, or a therapeutic agent that can block virus growth in host cells. Previously, we showed that rotavirus attaches to cells and enters them using several members of the integrin protein family that are present on the surface of the cells. Integrins are critical for cell adhesion, survival and communication. In this project, we will identify how rotavirus usage of integrins modulates cell functions. This will help us understand how rotavirus causes disease, how virus spreads in the body and how the immune response defends us from rotavirus. Rotavirus binds integrins using particular stretches of protein sequence that we have shown are also present in other human viral pathogens that cause hepatitis, AIDS and measles. We will determine if these other viruses also recognize integrins.Read moreRead less
Characterization Of Neutralizing Antibody Responses In HCV Infected Individuals.
Funder
National Health and Medical Research Council
Funding Amount
$478,076.00
Summary
Hepatitis C virus is a major human pathogen infecting 200 million people world-wide. Currently, there is no vaccine to prevent infection and treatment regimes are only partially effective. IInitial HCV infection is frequently asymptomatic and 30% of people spontaneously clear the virus. The remaining 70% of people develop a life-long chronic infection that causes progressive liver disease, cirrhosis and in some cases liver cancer. The reason why some people are able to clear virus has been attri ....Hepatitis C virus is a major human pathogen infecting 200 million people world-wide. Currently, there is no vaccine to prevent infection and treatment regimes are only partially effective. IInitial HCV infection is frequently asymptomatic and 30% of people spontaneously clear the virus. The remaining 70% of people develop a life-long chronic infection that causes progressive liver disease, cirrhosis and in some cases liver cancer. The reason why some people are able to clear virus has been attributed to the development of a strong cellular immune response and antibody is belived to play a monir role in achieving viral clearance. However, measurememnt of antibody responses in HCV infected pateints is routinely performed using conventional diagnostic tests that do not measure antibody that can help neutralize and clear virus. We have developed an assay that accurately measures the level of NAb in patient sera. We have found that chronically infected patients have broadly reactive neutralizing antibodies but that patients who clear virus, naturally or through treatment do not have broadly reactive neutralizing antibodies. Possibly explaining this phenomenon is that early during infection, antibody is frequently specific only to the infecting virus therefore to detect neutralizing antibodies, homologous viral sequences must be examined. In addition, we have found evidence that HCV can evade neutralzing antibodies through masking of sites to which antibodies bind. We propose to explore whether acutely infected patients develop NAb to autologous viral sequences, and how do these viral sequences and the antibody titre change throughout the course of infection and treatment. We also plan to determine the mechanism of neutralization resistance through the use of mutagenesis of resistant HCV glycoproteins. These studies are aimed at gaining a thorough understanding of the true role of antibody in HCV infection and its influence on viral evolution.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
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
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.
The Role Of The Inflammasome In Modulating Disease During Influenza Virus Infection
Funder
National Health and Medical Research Council
Funding Amount
$616,979.00
Summary
Highly pathogenic influenza A virus (IAV) infections in humans are associated with high mortality rates. This project will provide global and fundamental insights into our understanding of why IAV often cause fatal disease. It will advance knowledge of the mechanisms by which the host and virus interact and elucidate how the host's immune system responds to the infection and modulates disease, to facilitate the development of improved treatments for severe IAV infections.
Determination Of The Mechanisms Of Action Of A Cytomegalovirus Chemokine Receptor Homologue In Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$251,341.00
Summary
A number of herpesviruses encode proteins that are similar to proteins of our immune system. These pirated proteins are exploited by the virus to enable it to replicate and persist in the infected individual, usually by evading or gaining advantage from the normal immune response. This project will investigate the role of one such protein found in both human and animal herpesviruses (specifically cytomegaloviruses (CMV)) that is conserved with cellular cell surface proteins (receptors) that bind ....A number of herpesviruses encode proteins that are similar to proteins of our immune system. These pirated proteins are exploited by the virus to enable it to replicate and persist in the infected individual, usually by evading or gaining advantage from the normal immune response. This project will investigate the role of one such protein found in both human and animal herpesviruses (specifically cytomegaloviruses (CMV)) that is conserved with cellular cell surface proteins (receptors) that bind immune signaling molecules (chemokines). Chemokines are important proteins in the early response to infection. Binding of chemokines to their receptors initiates a cascade of signals within the cell that has profound effects on cellular responses to environmental stimuli. Thus, it is believed that herpesviruses have acquired chemokine receptors to modify or react to the immune response, causing infected cells to behave abnormally either despite or in response to chemokine signals. This project will determine how this CMV specific protein affects the function of cells that CMV infects and how this may promote virus replication, dissemination and persistence in infected hosts. We will also engineer CMVs where the activity of the target protein can be inhibited by administration of prototype antiviral drugs. If inhibition of the activity of the protein is found to reduce virus replication, dissemination or persistence, then this will demonstrate that this type of protein would be a suitable target for the development of novel drugs active against CMV infections. CMV can cause serious (potentially life threatening) disease in newborn children (following infection in the uterus) and immunosuppressed people (eg. organ transplant recipients and people with HIV-AIDS). Our studies will improve our understanding of the contribution of a specific CMV protein to disease, thereby assisting efforts to reduce the impact of CMV infections.Read moreRead less
The Role Of Noncoding Viral RNAs In Flavivirus Infection And Exosomal Signalling
Funder
National Health and Medical Research Council
Funding Amount
$683,447.00
Summary
The application is aimed at investigating the novel role for viral noncoding RNAs in exosomal antiviral signalling and associated outcome of infection with West Nile virus. We will identify host enzymes involved in generation of viral noncoding RNAs, determine which host proteins they interact with and how these interactions determine their incorporation into secreted exosomes to influence outcome of infection.
NEW INSIGHT INTO GLYCAN REQUIREMENTS FOR ROTAVIRUS-CELL ATTACHMENT AND ENTRY
Funder
National Health and Medical Research Council
Funding Amount
$1,068,758.00
Summary
Rotavirus causes significant infection and loss of life in children, particularly in underdeveloped countries. This project will investigate the role of carbohydrates as contact points for this deadly virus towards the goal of developing novel vaccines and drug therapies.