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.
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.
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
Understanding The Mechanisms Of Cytomegalovirus Induced Immunosuppression: Relevance To Viral Immunotherapies
Funder
National Health and Medical Research Council
Funding Amount
$467,310.00
Summary
Cytomegalovirus (CMV), measles and human immunodeficiency virus (HIV) are the three main human pathogens known to induce immunosuppression. The down-regulation of immune responses that characterizes a state of immunosuppression imparts the infecting pathogens the opportunity to escape immune surveillance and thus maximizes their chances to survive within their host, to replicate and be transmitted as required. The generalized immunosuppression caused by viral infection is often associated with s ....Cytomegalovirus (CMV), measles and human immunodeficiency virus (HIV) are the three main human pathogens known to induce immunosuppression. The down-regulation of immune responses that characterizes a state of immunosuppression imparts the infecting pathogens the opportunity to escape immune surveillance and thus maximizes their chances to survive within their host, to replicate and be transmitted as required. The generalized immunosuppression caused by viral infection is often associated with secondary infections with unrelated viral and-or bacterial pathogens, and as such represents a serious clinical problem. In humans, cytomegalovirus infection can cause tissue damage in normal individuals and may cause severe disease and even mortality in individuals with immature or compromised immune systems, such as newborns, AIDS patients, transplant recipients and patients undergoing chemotherapy. The severe complications that occur in the latter group of patients result from the combined effects of pre-existing and viral induced immunosuppression that often lead to severe secondary opportunistic infections. In transplant recipients however, CMV induced immunosuppression, in the absence of secondary infections, can be beneficial and has been associated with improved transplant outcome. The central aim of the work in the current proposal is to investigate the cellular and viral mechanisms involved in cytomegalovirus induced immunosuppression. The proposed studies will improve our understanding of viral interference with host immune responses and hence will be relevant to understanding the pathogenesis of CMV infection in humans and more importantly will provide critical insights into the rational design of suitable antiviral drugs and vaccines.Read moreRead less
Modulation Of Apoptosis By Cytomegalovirus: Analysis Of New Mechanisms To Interfere With Cytomegalovirus-induced Disease
Funder
National Health and Medical Research Council
Funding Amount
$697,084.00
Summary
Apoptosis, or programmed cell death is an essential process in developmental and homeostatic control of complex biological systems. In addition to these primary house keeping roles, apoptosis provides a powerful defence mechanism against invading pathogens, such as viruses, since it allows early elimination of infected cells from the host. A basic property of herpesviruses is their ability to establish persistent infection and remain in association with the host for its lifetime. This strongly u ....Apoptosis, or programmed cell death is an essential process in developmental and homeostatic control of complex biological systems. In addition to these primary house keeping roles, apoptosis provides a powerful defence mechanism against invading pathogens, such as viruses, since it allows early elimination of infected cells from the host. A basic property of herpesviruses is their ability to establish persistent infection and remain in association with the host for its lifetime. This strongly underlines their success at reaching an accommodation with the immune system's anti-apoptotic mechanisms. The central hypothesis of this project is that herpesviruses, such as murine and human cytomegalovirus, encode proteins that interfere with cell death pathways thereby circumventing host defence so that viral replication and dissemination can proceed. Thus, the aims are to identify and characterise cytomegalovirus proteins that modulate apoptosis. These studies will improve our understanding of the control of apoptosis during viral infection, especially as caused by cytomegaloviruses. Human cytomegalovirus (HCMV) is a pathogen able to cause significant morbidity and mortality in individuals with immature or compromised immune systems, such as newborns, AIDS patients, transplant recipients and people treated with chemotherapeutic drugs. Hence, the proposed studies will allow the elucidation of molecular mechanisms that may be relevant to the pathogenesis of HCMV in man and will provide insights into the rational design of suitable antiviral drugs and vaccines. Understanding viral mechanisms of host immune evasion continues to improve our understanding of complex cellular pathways. Therefore, given that abnormal regulation of apoptosis is implicated in the development of degenerative conditions, cancer and autoimmune disease, the proposed studies will provide valuable insight towards the development of new therapies for these pathological conditions.Read moreRead less
Viral Factors Involved In Flavivirus Replication And Virus-host Interactions
Funder
National Health and Medical Research Council
Funding Amount
$743,696.00
Summary
With our increased understanding of virus-host interactions it has become apparent that small, non-structural proteins and small RNAs of most viruses are vital for numerous, often multiple, functions in the viral life cycle. In the proposed project, we seek to gain a detailed understanding of the functions of small nonstructural protein NS2A and small abundant viral RNAs of medicaly important encephalitic flaviviruses, which have remained so far elusive and are at the cutting-edge in the researc ....With our increased understanding of virus-host interactions it has become apparent that small, non-structural proteins and small RNAs of most viruses are vital for numerous, often multiple, functions in the viral life cycle. In the proposed project, we seek to gain a detailed understanding of the functions of small nonstructural protein NS2A and small abundant viral RNAs of medicaly important encephalitic flaviviruses, which have remained so far elusive and are at the cutting-edge in the research field. We anticipate that with a better understanding of the roles of these factors in flaviviral replication and pathogenesis, novel targets for antiviral therapies and-or molecular determinants for inclusion in candidate vaccines will be identified.Read moreRead less
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
Multiple Cytomegalovirus Infections: Biological And Evolutionary Significance.
Funder
National Health and Medical Research Council
Funding Amount
$555,776.00
Summary
This project involves the study of cytomegalovirus (CMV) a common viral infection of humans which normally cause little disease. However in individuals whose immune system is suppressed (such as AIDS patients or transplant recipients), or in infection of pregnant women, CMV can cause serious or life-threatening disease in the patient or foetus. An interesting feature of CMV diseases in such patients is that enhanced viral growth and more severe disease is frequently associated with the presence ....This project involves the study of cytomegalovirus (CMV) a common viral infection of humans which normally cause little disease. However in individuals whose immune system is suppressed (such as AIDS patients or transplant recipients), or in infection of pregnant women, CMV can cause serious or life-threatening disease in the patient or foetus. An interesting feature of CMV diseases in such patients is that enhanced viral growth and more severe disease is frequently associated with the presence of multiple strains of CMV in the patient. We suggest that mixed CMV infections provide a survival advantage to the virus, with different strains within the mixed infection assisting the growth of other strains. This would result in increased virus growth overall, and enhanced disease. To study the mechanisms by which multiple infections with different CMV strains may affect both the virus and the host, experiments will be performed using an animal model of CMV, murine cytomegalovirus (MCMV). We will examine the effect of the presence of multiple strains of virus on virus growth and distribution within the infected host. We will also determine if functional MCMV strains are capable of assisting non-functional strains to survive within the host. These studies are relevant to the design of a CMV vaccine, and will be valuable in revealing the ways in which viruses can co-operate within an infection.Read moreRead less
Role Of Cytomegalovirus Class I Homologue In Interference With Host NK Cell Responses - A Potential Antiviral Target
Funder
National Health and Medical Research Council
Funding Amount
$428,020.00
Summary
A common property of herpesviruses such as cytomegalovirus is their ability to establish lifelong infection in their hosts. In humans, cytomegalovirus infection can lead to tissue damage in normal individuals and may cause severe disease and 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 ability of these viruses to establish persistent infection and remain in asso ....A common property of herpesviruses such as cytomegalovirus is their ability to establish lifelong infection in their hosts. In humans, cytomegalovirus infection can lead to tissue damage in normal individuals and may cause severe disease and 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 ability of these viruses to establish persistent infection and remain in association with the host for its lifetime is a consequence of their capacity to subvert normal host immune responses. This is achieved by destroying or mimicking the functions of molecules and-or pathways critical to normal host defence mechanisms. The viral gene product under investigation is similar to a cellular protein critical for the ability of immune cells to kill foreign and-or infectious agents. We will investigate the mechanisms by which this viral gene product interferes with the host's first line of defence against viral pathogens. The proposed studies will improve our understanding of the strategies used by viruses to escape normal host immune responses and hence provide insights into the rational design of antiviral drugs and vaccines. Since the viral protein under investigation is similar to a cellular protein essential for the ability of immune cells to kill foreign or infectious agents, an improved understanding of the mechanisms of action of this protein will continue to improve our understanding of cellular events which play a crucial role in immune responses involved not only in control of infection, but also in tumour growth and transplant survival. Thus, the proposed studies will provide valuable insight towards the development of new therapies for pathological conditions associated with the above.Read moreRead less