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
Defining The Molecular Effectors And Regulators Of Anti-viral Immune Responses
Funder
National Health and Medical Research Council
Funding Amount
$447,750.00
Summary
In humans, cytomegalovirus infection can cause severe disease and may even be fatal in individuals with immature or compromised immune systems, such as newborns, AIDS patients, transplant recipients and people treated with chemotherapeutic drugs. The majority of healthy individuals however can clear the infection with minimal disease. The ability of cytomegalovirus to cause disease is increased in the absence of effective immune responses which would normally clear the virus before illness occur ....In humans, cytomegalovirus infection can cause severe disease and may even be fatal in individuals with immature or compromised immune systems, such as newborns, AIDS patients, transplant recipients and people treated with chemotherapeutic drugs. The majority of healthy individuals however can clear the infection with minimal disease. The ability of cytomegalovirus to cause disease is increased in the absence of effective immune responses which would normally clear the virus before illness occurs. Understanding the role of specific mediators of anti-viral immune responses is therefore of paramount importance in establishing the guidelines for the design of more effective anti-viral therapies. The mouse model of cytomegalovirus infection provides a unique system to dissect the roles of specific components of the immune response during the course of viral infection. Our previous studies have shown that anti-viral immune responses are complex and involve a multitude of players. The central aim of the work in the current proposal is to establish the precise contribution of specific molecular effectors and regulators of anti-viral immune responses and define their relevance during the different stages of viral infection. Hence, the results of these studies will be relevant to understanding the pathogenesis of cytomegalovirus infection in humans and more importantly will provide critical insights into the rational design of improved antiviral drugs and vaccines. Since the molecules and cells under investigation are also known to play a crucial role in immune responses that control tumour growth and transplant survival, the proposed studies will provide valuable insight towards the development of new therapies for pathologies associated not only with cytomegalovirus infection, but also with the conditions named above.Read moreRead less
Improving Adaptive Anti-viral Responses: A Key To Eliminating Persistent Viral Infection
Funder
National Health and Medical Research Council
Funding Amount
$402,391.00
Summary
Cytomegalovirus (CMV) can cause a persistent infection that can result in adverse clinical outcomes. Our previous work established that suboptimal adaptive immunity is responsible for viral persistence. This proposal will define the defect in adaptive immunity, its causes and how to improve it. The understanding gained from the proposed studies will provide crucial information for the development of improved anti-viral therapies and vaccines.
Antigen Dose And TCR Repertoire In CD8+ T Cell Immunodominance Hierarchies
Funder
National Health and Medical Research Council
Funding Amount
$558,920.00
Summary
The CD8+, or killer , T lymphocytes (white blood cells) are the hit men of immunity, recirculating continually around the body to eliminate other cells that are dangerous because they are cancerous or infected with a virus. A major difficulty is that killer T cells also exert selective pressures that cause viruses and tumours to mutate and thus avoid immune control. This is a particularly serious problem for RNA viruses that readily mutate as they divide. These include the human immunodeficiency ....The CD8+, or killer , T lymphocytes (white blood cells) are the hit men of immunity, recirculating continually around the body to eliminate other cells that are dangerous because they are cancerous or infected with a virus. A major difficulty is that killer T cells also exert selective pressures that cause viruses and tumours to mutate and thus avoid immune control. This is a particularly serious problem for RNA viruses that readily mutate as they divide. These include the human immunodeficiency virus (HIV) that causes AIDS and, while the mutations that are most important with influenza viruses are those that modify viral surface proteins recognized by antibodies, such T cell escape mutants can also be a problem with influenza. The other reason why there is particular interest in promoting CD8+ T cell-mediated immunity to influenza is that the killer T cells are very cross-reactive. We have shown that vaccination approaches that prime mouse CD8+ T cells to resist influenza A viruses circulating currently in humans will also protect against the highly lethal, and dangerous H5N1 bird 'flu. The present flu vaccines only stimulate antibodies, so there is interest in the possibility of a major re-design. The CD8+ T cells recognize tiny elements (peptides) of the virus or tumour bound in the tip of our own transplantation, or class I major histocompatibility complex (MHCI) molecules. These pMHCI complexes are called epitopes. The focus here is on the use of novel genetic engineering strategies to find out how, when the virus mutates to disrupt the major epitopes seen by killer T cells, other minor epitopes can be abnormally emphasized in a way that promotes effective immune control. As we work on this with the relatively simple and safe influenza model we will concurrently develop strategies that may be of value in HIV and tumour immunity. Solving this problem could prove to be a substantial advance in the design of vaccines and immunotherapy approaches.Read moreRead less
Argonaute Proteins In The Mammalian Antiviral Response
Funder
National Health and Medical Research Council
Summary
Viruses are the most abundant infectious agents on earth, and the diseases caused by them are a constant threat and cause of mortality worldwide. Awarded the Nobel Prize for Medicine in 2006, RNA interference (RNAi) is a natural process that plants use to attack viruses. Humans possess all of the tools for RNAi, but whether it is used for antiviral defense is unknown. This study aims to uncover this immune process which will open new avenues to treat virus infections, such as influenza and HIV.
Systematically Exploring The Contribution Of Immunoproteasome To Immunodominance And T Cell Function
Funder
National Health and Medical Research Council
Funding Amount
$499,860.00
Summary
Vaccine will help us to fight both infectious diseases and malignancy. However, there are few successful vaccines for infectious agents and there is simply no vaccine to cure any tumor at the moment. So, it is essential for us to learn the basics related to vaccine development. Killer T cells eliminate tumour cells or virally infected host cells by recognising fragments (epitopes) derived from tumour- or virus-derived proteins displayed on a host molecule called MHC. Normally multiple epitopes a ....Vaccine will help us to fight both infectious diseases and malignancy. However, there are few successful vaccines for infectious agents and there is simply no vaccine to cure any tumor at the moment. So, it is essential for us to learn the basics related to vaccine development. Killer T cells eliminate tumour cells or virally infected host cells by recognising fragments (epitopes) derived from tumour- or virus-derived proteins displayed on a host molecule called MHC. Normally multiple epitopes are generated as part of the protein recycling program referred as proteine degradation which is mainly conducted by bundled enzyme complex, called proteasome. Two major forms of proteasomes are expressed by most cells. One called house-keeping proteasome and the other, which replaces the house-keeping one during viral infections is called immunoproteasome. The role that the immunoproteasome plays during anti-viral and anti-tumoral immune responses is not fully understood. In addition, the immunoproteasome is also expressed by a few cell types that do not suppose to need it if its function is entirely to generate better epitopes for MHC to display. In this project, we will sytematically explore the contribution of the immunoproteasome to overall anti-viral and anti-tumoral immune responses in three mouse model systems. The shared feature of these systems is that multiple killer T cell epitopes have been defined, which could potentially provide us with very sensitive assessments. The three systems are anti-influenza, anti-vaccinia virus and anti-tumor antigen (NY-ESO-1) mouse models.Read moreRead less
Mechanisms Of Virally-induced Immunosuppression: Effects On DC-NK Networks
Funder
National Health and Medical Research Council
Funding Amount
$566,308.00
Summary
Cytomegalovirus (CMV) infection induces immunosuppression that often results in adverse clinical outcomes. Our previous work established that dendritic cells (DC), cells involved in the initiation of immune responses, are a principle target for CMV. This proposal will test the hypothesis that CMV-induced immunosuppression is mediated by viral interference with DC. Understanding the mechanisms involved in the induction of immunosuppression is a crucial step towards developing better therapies.
Host-virus Interactions That Define The Outcome Of Anti-viral T Cell Responses: Relevance To Viral Persistence
Funder
National Health and Medical Research Council
Funding Amount
$487,500.00
Summary
Infection with human cytomegalovirus (hCMV) is normally resolved without symptomatic evidence of infection. However, severe hCMV disease can occur in immunocompromised patients in which the manifestations of disease include chorioretinitis, interstitial pneumonia and hepatitis. In immunologically immature children, congenital infection results in cytomegalic inclusion disease (CID). CID in infants causes severe neurological sequelae resulting in mental retardation, deafness and blindness. Vaccin ....Infection with human cytomegalovirus (hCMV) is normally resolved without symptomatic evidence of infection. However, severe hCMV disease can occur in immunocompromised patients in which the manifestations of disease include chorioretinitis, interstitial pneumonia and hepatitis. In immunologically immature children, congenital infection results in cytomegalic inclusion disease (CID). CID in infants causes severe neurological sequelae resulting in mental retardation, deafness and blindness. Vaccination against hCMV induced cytomegalic inclusion disease has been designated Level I (most favourable) due to the prediction that it could save lives and prevent life-long disability. Given the essential nature of CD8 T cells in CMV control and the high prevalence of CMV in society, it will be crucial to develop a vaccine capable of eliciting an efficacious T cell response which develops lasting memory. We hypothesise that mCMV has evolved mechanisms for generating an appropriate T cell response involved in viral control and the establishment of a persistent infection. The central aim of the work in the current proposal is to investigate the cellular and viral mechanisms involved in the generation of cytomegalovirus specific T cells. The proposed studies will improve our understanding of the generation of anti-viral T cell responses and hence will be relevent to further our understanding of the role of T cells in human infection. More importantly the results will provide critical insights into the rational design of suitable antiviral drugs and vaccines.Read moreRead less
Inhibition Of Interferon-alpah-beta By Chikungunya Virus And The Induction Of Arthritis
Funder
National Health and Medical Research Council
Funding Amount
$709,193.00
Summary
Chikungunya virus is a mosquito borne virus which has caused epidemics of arthritis around the world (recently 260,000 people Reunion Island, France and 1.6 million people in India). The virus is ordinarily very sensitive to the main mammalian anti-viral defence system (interferon alpha-beta). This grant seeks to understand how, despite the activation of this system during infection, the virus manages to persist and cause 3-6 months of debilitating arthritis.
Interaction Of Anti-viral IDO And NOS2 In Vivo In A Novel Murine STD Model.
Funder
National Health and Medical Research Council
Funding Amount
$573,629.00
Summary
Sexually transmitted viral diseases (STD) are increasing globally, but we know little of how virus is controlled early in infection. We have shown for the first time in vivo, in our STD model, that during an antiviral immune response, soluble factors turn on an enzyme, indoleamine 2,3-dioxygenase (IDO), to break down and deplete the amino acid, L-tryptophan, starving virus to reduce growth early in STDs. Our project will further define the action and control of IDO in STD.