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
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
In Vivo Imaging Of Virus-specific T Cell Responses In The Skin
Funder
National Health and Medical Research Council
Funding Amount
$332,258.00
Summary
Effective vaccination against many viral infections such as Herpes Simplex Virus (HSV) may be achieved by directing the cells of the immune system to specific sites in the body where they can lie in wait against the disease. To direct the immune system in this way, we must first understand how immune cells orchestrate themselves in tissues. This project will utilise advanced imaging techniques to study immune cells in real time to understand how they protect against viral infections in the skin.
The Role Of T Cell Receptor Avidity In Determining T Cell Repertoires And Responses
Funder
National Health and Medical Research Council
Funding Amount
$472,500.00
Summary
T cells are an essential component of the immune system. CD8 T cells, in particular, play a vital role in the immune response to viruses and tumors, predominantly via killing of virally infected cells and tumor cells, as well as the release of inflammatory mediators. T cells must be activated before they can mediate such anti-viral or anti-tumor effects and this activation occurs through the binding of pathogen or tumor fragments (peptides) by a receptor on the surface of T cells (T cell recepto ....T cells are an essential component of the immune system. CD8 T cells, in particular, play a vital role in the immune response to viruses and tumors, predominantly via killing of virally infected cells and tumor cells, as well as the release of inflammatory mediators. T cells must be activated before they can mediate such anti-viral or anti-tumor effects and this activation occurs through the binding of pathogen or tumor fragments (peptides) by a receptor on the surface of T cells (T cell receptor). Each individual has an entire repertoire of T cells with unique T cell receptors which interact with peptides with varying binding strengths. After stimulation of T cells by e.g. viral infection, a subset of the T cell repertoire will become expanded and dominate the anti-viral immune response. This study aims to investigate how, during a viral infection, the strength (or 'avidity') of the interaction between the T cell receptor and the peptide influences (i) whether or not a T cell clone is recruited into the immune response and, if so, its dominance over other clones within that response, and (ii) how efficiently a T cell is activated. It is anticipated that particular virus peptide-specific T cell populations with an overall high avidity will be better able to produce inflammatory mediators and kill infected cells compared to lower avidity T cell populations specific for a different virus peptide. It is also expected that the higher avidity populations will exhibit greater diversity of TCRs. Further, within peptide-specific populations, it is anticipated that the relatively high avidity T cell clones will dominate the specific response. This study will contribute to a greater understanding of factors contributing to T cell recruitment and activation. Armed with this knowledge we will be better able to design vaccines to elicit optimal T cell responses to viral infection.Read moreRead less
Competition For Polarity Influences Lymphocyte Signaling And Function
Funder
National Health and Medical Research Council
Funding Amount
$500,460.00
Summary
Infectious diseases caused by viruses and bacteria remain a significant health problem. CD46 is a protein on the surface of human cells that is used by a number of viruses and bacteria to enter and infect host cells. Through binding to the CD46 protein, viruses and bacteria can induce changes in immune cells, such as T lymphocytes, that affect the way our immune system responds to infection. For example, immunosuppression induced by infection with measles virus is the primary cause of the mortal ....Infectious diseases caused by viruses and bacteria remain a significant health problem. CD46 is a protein on the surface of human cells that is used by a number of viruses and bacteria to enter and infect host cells. Through binding to the CD46 protein, viruses and bacteria can induce changes in immune cells, such as T lymphocytes, that affect the way our immune system responds to infection. For example, immunosuppression induced by infection with measles virus is the primary cause of the mortality and morbidity associated with the disease, and is a phenomenon that is poorly understood. However, there is evidence to suggest that the interaction between measles-infected cells with CD46 on the immune cells is partly responsible for the immunosuppression observed. Our laboratory has recently found that binding of CD46 (by antibody or measles antigen) on immune cells provides a signal to the cell to change its polarisation state (the way proteins are distributed within the cell) and impairs their ability to recognize and kill target cells, and become activated. These observations indicate a new paradigm by which competition of receptor signals for polarization determines signalling outcomes and provides a possible mechanism for how pathogens that bind CD46, such as measles, subvert normal immune cell communication and induce immunosuppression. This proposal aims to investigate the mechanisms behind the effect of polarising signals on immune cells, and will specifically use CD46 and measles virus as a model. The outcomes of this study will define new paradigms in lymphocyte biology and dissect the key pathways that underpin how CD46 influences immune outcome in response to infection.Read moreRead less
Costimulatory Mechanisms For Enhancing CD8 T Cell Responses During An Acute Respiratory Infection
Funder
National Health and Medical Research Council
Funding Amount
$438,750.00
Summary
Following an infection, a person's immune system responds to fight the pathogen. One of the most important consequences of the immune response to an infectious disease is the establishment of memory to that particular disease so that a person is able to clear the same pathogen faster upon subsequent exposures. This memory is due to specific cells called memory lymphocytes. One subset of these cells are called CD8+ T cells and these are important for controlling and clearing viral infections. New ....Following an infection, a person's immune system responds to fight the pathogen. One of the most important consequences of the immune response to an infectious disease is the establishment of memory to that particular disease so that a person is able to clear the same pathogen faster upon subsequent exposures. This memory is due to specific cells called memory lymphocytes. One subset of these cells are called CD8+ T cells and these are important for controlling and clearing viral infections. New vaccine strategies are aimed at improving CD8 T cell responses so that they are more effective at fighting diseases such as HIV which causes AIDS and Hepatitis C virus. The mechanisms which lead to long lived memory CD8 T cells are not well understood. This research will characterise the function of genes involved in activating CD8 T cells and producing more memory CD8 T cells. The influenza model will be used as it is a well characterised model for studying anti-viral immunity. This project involved studying the mechansims of known genes involved in CD8 T cell responses to influenza. Also the discovery of new genes which are involved in CD8 T cell memory will be identified and characterised using new novel technologies, such as ENU mutagenesis, that only now are able to be utilised since the mouse genome (DNA) has been sequenced. This research will provide a basis for design of new and more effective vaccines.Read moreRead less
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