Determinants Of Cytomegalovirus Salivary Gland Persistence
Funder
National Health and Medical Research Council
Funding Amount
$566,308.00
Summary
Human cytomegalovirus (HCMV) persists for extended periods in the salivary gland, an organ of viral transmission. It is not clear how the virus avoids immune mediated control in this tissue. This aspect of viral pathology will be assessed in a mouse model using two strains of murine CMV which exhibit marked differences in salivary gland persistence. The role of tissue tropism (inhibition of apoptosis), viral immune evasion and host immunity in salivary gland persistence will be studied.
Mechanisms Regulating Establishment Of Persistent Herpesvirus Infection
Funder
National Health and Medical Research Council
Funding Amount
$511,446.00
Summary
Herpesviruses are a major cause of disease worldwide and are amongst the most successful human pathogens, with some viruses infecting more than 80% of the world's population. This group of viruses persist and reactivate in hosts and induce immunosuppression.The control of herpesviruses infections thus represents an important clinical goal. Understanding the mechanisms involved in the induction of viral persistence and immunosuppression is a crucial step towards developing better therapies.
Human cytomegalovirus (HCMV) is a classic example of a group of herpes viruses, which is found universally throughout all geographic locations and socioeconomic groups, and infects 50% of adults in developed countries. HCMV infection is important to certain high-risk groups. Major areas of concern are: (1) the risk of infection to unborn baby during pregnancy, (2) the risk of infection to people who work with children, and (3) the risk of infection to immunocompromised persons (e.g. organ transp ....Human cytomegalovirus (HCMV) is a classic example of a group of herpes viruses, which is found universally throughout all geographic locations and socioeconomic groups, and infects 50% of adults in developed countries. HCMV infection is important to certain high-risk groups. Major areas of concern are: (1) the risk of infection to unborn baby during pregnancy, (2) the risk of infection to people who work with children, and (3) the risk of infection to immunocompromised persons (e.g. organ transplant patients and HIV-infected individuals). Epidemiological studies have shown that 80%-90% of developing unborn babies who acquire congenital HCMV infection displays a variable pattern of pathological sequelae within the first few years of life that may include hearing loss, vision impairment and mental retardation. There is an increasing argument that a reduction in HCMV load will have a significant effect on the sequelae associated with congenital HCMV infection. Indeed, vaccination provides the most practical modality of achieving such a reduction in HCMV load. To develop such a vaccine, formulation based on viral antigens that activate both protective cellular and humoral responses needs to be tested to assess its immunogenicity. No such vaccine is presently available for HCMV. In this application we have sought to develop a prophylactic vaccine and to test its efficacy in a immunocompetent transgenic mouse model and as well under conditions of immunosuppression (CD4 T cell deficient). The overall strategy is to use this prophylactic vaccine to stimulate the cellular (CD8+ and CD4+ T cells) and humoral responses against multiple HCMV antigens. This vaccine will be based on the novel chimeric polyepitope technology and exploits a novel replication deficient adenovirus expression system which has recently been approved for human use.Read moreRead less
Effects Of Natural Sequence Variation On Evasion Of Cytotoxic T Lymphocytes By Murine Cytomegalovirus.
Funder
National Health and Medical Research Council
Funding Amount
$553,167.00
Summary
Human cytomegalovirus persists for the life time of an infected person. It has many ways of achieving this, including interfering with the host immune response. This project seeks to explore this using a mouse model and murine CMV. Specifically we will focus on a set of viral genes that inhibit host recognition of virally infected cells. Sequence variation in these genes suggests that they function differently in different strains of virus: we will examine the consequences of this variation.
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
Molecular Mechanisms Of Persistence Of Mycobacterium Tuberculosis
Funder
National Health and Medical Research Council
Funding Amount
$398,142.00
Summary
Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB. It infects about third of all people in the world and kills several million people each year. People with active TB spread the mycobacteria in aerosols from their breath. When another person inhales an infected aerosol the mycobacteria enter their lungs and establish a new infection. During the course of infection M. tuberculosis is exposed to a variety of harsh environments inside the lungs which normally kill other bacte ....Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB. It infects about third of all people in the world and kills several million people each year. People with active TB spread the mycobacteria in aerosols from their breath. When another person inhales an infected aerosol the mycobacteria enter their lungs and establish a new infection. During the course of infection M. tuberculosis is exposed to a variety of harsh environments inside the lungs which normally kill other bacteria. M. tuberculosis is able to survive and adapt to those harsh environments. M. tuberculosis has an especially thick and tough cell wall which protects it. M. tuberculosis can adapt to the environments it encounters in a patient by changing their cell walls. The wall also protects mycobacteria from chemicals so it is resistant to many common antibiotics. There are some drugs to treat TB however M. tuberculosis is building up resistance to those drugs so we need to find new ones We will determine how mycobacteria synthesize their special cell wall and how they adapt during an infection. If we know how the details of how M. tuberculosis protects itself then we can find potential weakness which could be targets for the development of new drugs to treat TB.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
The Impact Of Interplays Between Viral Immune Evasion Proteins And Host Cell-surface Receptors On Viral Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$482,710.00
Summary
Herpesviruses can cause infections that persist for the lifetime of the individual. These viruses have evolved a range of mechanisms to evade the host's immune response that would otherwise eliminate them. One member of the herpesvirus family that is replete with methods for avoiding the immune response is cytomegalovirus. This virus, while not causing symptoms in healthy people, is a significant cause of disease and mortality in indivuals who are immunosuppressed such as AIDS patients or people ....Herpesviruses can cause infections that persist for the lifetime of the individual. These viruses have evolved a range of mechanisms to evade the host's immune response that would otherwise eliminate them. One member of the herpesvirus family that is replete with methods for avoiding the immune response is cytomegalovirus. This virus, while not causing symptoms in healthy people, is a significant cause of disease and mortality in indivuals who are immunosuppressed such as AIDS patients or people undergoing transplantation, or in neonates who have poorly developed immune responses. In the current project we will explore how virally encoded proteins that bind to cell surface receptors expressed on a class of immune effector cell called the Natural Killer (NK) cell, can interfere with the functions of these cells. We will seek to define the NK cell proteins that are specifically bound by these viral proteins and also make deletion mutants of these viral genes to assess what effect knocking out these genes has on virus-caused disease. These studies will provide important insights into novel mechanisms of viral immune evasion and may provide insights into how therapies could be developed that interfere with the functions of these viral proteins.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
Novel Immune Evasion Strategy Of CMV: Targeting Of An Adhesion Molecule Involved In Leukocyte Recruitment/activation.
Funder
National Health and Medical Research Council
Funding Amount
$391,650.00
Summary
Herpesviruses cause persistent lifelong infection. To achieve this they have evolved a variety of mechanisms to evade the immune response mounted to combat them. They also minimise the expression of their gene products to a minimal suite of latency associated proteins. One member of the herpesvirus family is cytomegalovirus. While in healthy individuals it causes aymptomatic infection, it causes significant disease and mortality in individuals whose immune systems are suppressed such as transpla ....Herpesviruses cause persistent lifelong infection. To achieve this they have evolved a variety of mechanisms to evade the immune response mounted to combat them. They also minimise the expression of their gene products to a minimal suite of latency associated proteins. One member of the herpesvirus family is cytomegalovirus. While in healthy individuals it causes aymptomatic infection, it causes significant disease and mortality in individuals whose immune systems are suppressed such as transplant and AIDS patients, and also in the fetus which has a poorly developed immune system. Cytomegaloviruses set up persistent and latent lifelong infections. In the current proposal we will be assessing a viral gene present in mouse cytomegalovirus that codes for a protein that binds to a cellular adhesion molecule. This adhesion molecule called CD44 is involved in the migration of immune effector cell to sites of infection and in their activation. The viral gene thus represents a potential immune evasion molecule with the ability to subvert the host's immune response by reducing the infiltration and-or activation of cells that clear virus infection. The results from these studies could help us design anti-viral drugs that interfere with the effect of this viral protein, thus providing a novel anti-viral treatment strategy.Read moreRead less