Populations of viruses in an host can be very diverse and just as the behaviour of a population of humans can be very different to the behaviour of individuals in them, populations of viruses behave differently to the behaviour of individuals in them. This diversity may provide a survival advantage to the virus and it also may regulate the severity of the symptoms in an infected host. This study will provide important new information that will drive vaccine strategies and public health policy.
The diversity of HIV quasispecies within a single AIDS patient is far greater than the global diversity of influeneza annually, highlighting the enormous burden HIV imposes on the immune network. The capacity of HIV-1 to evolve quickly has significantly impaired our effort to produce effective vaccine and long lasting treatment strategy. This project utilizes multidisciplinary approaches to delineate determinants that drives the diversification of HIV-1.
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
Defining The Requirement For The Inhibition Of Bak To The Pathogenesis Of Cytomegalovirus Infection
Funder
National Health and Medical Research Council
Funding Amount
$592,661.00
Summary
Apoptosis, or programmed cell death is a powerful defence mechanism against viral infection. Thus, to replicate efficiently viruses have evolved means to inhibit apoptosis. The central aim of this work is to understand how cytomegalovirus prevents cell death protein during infection. The proposed studies will improve our understanding of the mechanisms that regulate viral replication and will contribute insights into the normal processes that control cell survival.
Current combination antiviral therapy can't cure an HIV infection because long-lived T-cells carrying latent HIV DNA can rekindle the infection when drugs are removed. We will study elements in HIV genetic code that control expression of HIV proteins from latent HIV. A detailed molecular understanding of the structure and function of these HIV RNA elements and the viral and host cell factors that interact with them will expose new targets for therapy of latent HIV.
Polarized Epithelia And The Natural History Of Hepatitis Viruses
Funder
National Health and Medical Research Council
Funding Amount
$358,770.00
Summary
The viruses causing hepatitis in man must cross specialised cell layers in the body to reach the liver, and must again cross these cell layers and liver cells in order to be transmitted to subsequent hosts. This research will examine how each of the hepatitis viruses (HAV to HEV) are able to enter and exit the body, and the role that these mechanisms may play in the development of acute disease and of chronic infections with hepatitis B and C viruses. The findings will contribute to development ....The viruses causing hepatitis in man must cross specialised cell layers in the body to reach the liver, and must again cross these cell layers and liver cells in order to be transmitted to subsequent hosts. This research will examine how each of the hepatitis viruses (HAV to HEV) are able to enter and exit the body, and the role that these mechanisms may play in the development of acute disease and of chronic infections with hepatitis B and C viruses. The findings will contribute to development of improved methods for the prevention and control of viral hepatitis.Read moreRead less
The Role Of Vif In Enhancing HIV Replication And Effecting The Integrity Of The Replication Complexes Of HIV
Funder
National Health and Medical Research Council
Funding Amount
$260,200.00
Summary
HIV-AIDS is still one of the leading causes of infectious human fatality worldwide. The genome of HIV encodes six viral accessory proteins that are necessary for viral replication and infection. One of these genes, viral infectivity factor (vif), is essential for production of infectious virus. Exactly how this viral protein works within the cell is not clear at present. Current literature suggests that Vif acts in some way to enhance reverse transcription, one of the early stages of the viral l ....HIV-AIDS is still one of the leading causes of infectious human fatality worldwide. The genome of HIV encodes six viral accessory proteins that are necessary for viral replication and infection. One of these genes, viral infectivity factor (vif), is essential for production of infectious virus. Exactly how this viral protein works within the cell is not clear at present. Current literature suggests that Vif acts in some way to enhance reverse transcription, one of the early stages of the viral life cycle. We aim to investigate the action of Vif in stabilizing early HIV reverse transcription complexes to understand how it acts to enhance HIV replication and viral infection. The early stages of HIV replication are critical for establishing infection and hence ideal targets for therapeutic intervention. This research will help understand how Vif works in a cell and affects the infectivity of HIV viral particles and may be suggestive of potential targets for development of anti-viral drugs.Read moreRead less
Regulation Of Viral Latency In Gamma-herpesvirus Infection
Funder
National Health and Medical Research Council
Funding Amount
$258,000.00
Summary
The cost to public health from herpesvirus infection is enormous. The gamma-herpesviruses chronically infect more than 95% of the world's population. This group of viruses induce a state of immunosuppression that cause down-regulation of immune responses. This allows the virus the opportunity to evade the immune system and thus survive within the host. The gamma-herpesviruses do not generally cause serious disease in normal individuals but reactivation of gamma-herpesviruses can cause severe dis ....The cost to public health from herpesvirus infection is enormous. The gamma-herpesviruses chronically infect more than 95% of the world's population. This group of viruses induce a state of immunosuppression that cause down-regulation of immune responses. This allows the virus the opportunity to evade the immune system and thus survive within the host. The gamma-herpesviruses do not generally cause serious disease in normal individuals but reactivation of gamma-herpesviruses can cause severe disease, even mortality, in individuals with an immature or a compromised immune system. Viral reactivation is a major complication of immunosuppressive diseases such as HIV (which currently affects more than 45 million people) and in transplant recipients. The virally-induced changes in the host cells can result in the development of secondary infections, post-transplantation lymphoproliferative disease and even the development of tumours. The central aim of the studies described in this proposal is to understand the cellular and viral mechanisms regulating how the virus is maintained in the host. These studies will improve our understanding of how antigen presenting cells and CD8+ T lymphocytes ensure an immune response is maintained and may identify critical targets to facilitate the rational design of antiviral drugs and vaccines.Read moreRead less
Defining The Mechanisms That Regulate Effective Long-term Anti-viral Immunity
Funder
National Health and Medical Research Council
Funding Amount
$547,315.00
Summary
Human cytomegalovirus (HCMV) is a common human pathogen which normally causes a mild or even asymptomatic infection. However, in immunocompromised individuals, HCMV causes severe disease whose manifestations include chorioretinitis, interstitial pneumonia and hepatitis. Similarly, in neonates lacking a fully mature immune system, HCMV causes severe morbidity. Vaccines that protect against HCMV induced cytomegalic inclusion disease have been designated Level I (most favourable) due to the predict ....Human cytomegalovirus (HCMV) is a common human pathogen which normally causes a mild or even asymptomatic infection. However, in immunocompromised individuals, HCMV causes severe disease whose manifestations include chorioretinitis, interstitial pneumonia and hepatitis. Similarly, in neonates lacking a fully mature immune system, HCMV causes severe morbidity. Vaccines that protect against HCMV induced cytomegalic inclusion disease have been designated Level I (most favourable) due to the prediction that they could save lives and prevent life-long disability. Similarly, therapies that prevent and-or reduce HCMV reactivation will significantly improve the prognosis of transplant and AIDS patients. The murine CMV (MCMV) infection model has provided important insights as to how the immune system controls infection, and the mechanisms utilized by the virus to circumvent these processes. The design of effective therapies and vaccines requires a thorough understanding of the mechanisms required to generate and maintain long-lasting anti-viral responses. The studies outlined in this proposal aim to define the impact of specific components of the immune system n the generation, maintenance and effectiveness of anti-viral immunity. The well characterized MCMV model will be used to address these issues.Read moreRead less