The Effect Of Innate Immune Responses On The Induction Of Protective Immunity In Murine Typhoid Fever
Funder
National Health and Medical Research Council
Funding Amount
$136,500.00
Summary
Salmonella are important pathogens of humans causing diseases ranging from gastroenteritis, typhoid fever to arthritis. Like most if not all infections, the early interaction between the host and the bacterium is characterised by very non-specific symptoms. These non-specific symptoms arise because the so-called innate immune system is activated by the infection. The purpose of this grant is to establish whether these non-specific symptoms, caused by the release of immunological homrones called ....Salmonella are important pathogens of humans causing diseases ranging from gastroenteritis, typhoid fever to arthritis. Like most if not all infections, the early interaction between the host and the bacterium is characterised by very non-specific symptoms. These non-specific symptoms arise because the so-called innate immune system is activated by the infection. The purpose of this grant is to establish whether these non-specific symptoms, caused by the release of immunological homrones called cytokines, are essential to the development of an effective immune response which can protect against subsequent re-infection. This study has important implications for vaccines, of our understanding of how bacteria cause disease, and the role-capacity of the innate immune system in the development of immunity.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
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
Biology Of The Novel C-type Lectin Receptor DCL-1 In Innate And Adaptive Immune Response
Funder
National Health and Medical Research Council
Funding Amount
$439,500.00
Summary
The innate immune system is the first line of defense in protecting the body from infection. Phagocytic (meaning eating) white blood cells, which include dendritic cells and macrophages are equipped with cell surface proteins These bind the many types of microbes that cause infection, allowing the phagocytes to destroy them (innate immune response). Furthermore, dendritic cells and macrophages have mechanisms to activate additional specific responses (adaptive immune response) mediated by lympho ....The innate immune system is the first line of defense in protecting the body from infection. Phagocytic (meaning eating) white blood cells, which include dendritic cells and macrophages are equipped with cell surface proteins These bind the many types of microbes that cause infection, allowing the phagocytes to destroy them (innate immune response). Furthermore, dendritic cells and macrophages have mechanisms to activate additional specific responses (adaptive immune response) mediated by lymphocytes (T and B cells). We have discovered a cell surface protein, termed DCL-1, which may play a role in uptake of microbes by phagocytes and activation of innate and adaptive immune responses. This project will examine the mechanisms whereby DCL-1 mediates these immune responses. Understanding the mechanism may allow us to exploit DCL-1 for tumor immunotherapy.Read moreRead less
Role Of P2X7 In Innate And Adaptive Immunity To Mycobacterial Infections
Funder
National Health and Medical Research Council
Funding Amount
$472,500.00
Summary
Tuberculosis remains an enormous global health problem. Some 32% of the world s population are infected, with over 2 million persons dying each year. It is not well understood why some infected individuals develop clinical disease yet others remain healthy, but many cases are due to reactivation of dormant organisms lying within a specialized white cell, the macrophage. We know that declining socio-economic conditions, HIV co-infection, and some genetic risk factors such as HLA type contribute t ....Tuberculosis remains an enormous global health problem. Some 32% of the world s population are infected, with over 2 million persons dying each year. It is not well understood why some infected individuals develop clinical disease yet others remain healthy, but many cases are due to reactivation of dormant organisms lying within a specialized white cell, the macrophage. We know that declining socio-economic conditions, HIV co-infection, and some genetic risk factors such as HLA type contribute to the likelihood of an individual developing disease, but current known factors are insufficient to fully account for the risk of an infected individual developing disease. We have recently shown that the tuberculosis bacteria can be killed by the addition of a natural compound, ATP, to infected macrophages. This process occurs when ATP activates the P2X7 receptor leading to mycobacterial killing. We have identified several polymorphisms (mutations) in the P2X7 receptor. In individuals with one particular polymorphism, designated A1513C, these people do not respond to ATP and do not kill tuberculosis using this pathway. TB patients who are heterozygous for the A1513C polymorphism show approximately a 50% reduction in mycobacterial killing. We have preliminary evidence that this A1513C polymorphism is expressed at an over represented frequency in TB patients we have tested, suggesting that having this polymorphism may increase your risk of developing tuberculosis. The aim of this project is two fold. One, we will investigate the functioning of this receptor, determining how the P2X7 receptor is activated and how it interacts with other molecules in the immune system to kill tuberculosis. Secondly we shall determine if polymorphisms in the P2X7 receptor are a risk factor for the development of tuberculosis and leprosy disease.Read moreRead less
Characterisation Of Cell-mediated Immune Responses In Burkholderia Pseudomallei Infection
Funder
National Health and Medical Research Council
Funding Amount
$239,250.00
Summary
The bacterium Burkholderia pseudomallei, causes a life threatening condition known as melioidosis. Melioidosis is emerging as an important infectious disease in tropical regions of Australia and South East Asia. Death rates following acute disease are extremely high. Despite the importance of B. pseudomallei in tropical public health, very little is known regarding how the body's defence mechanisms prevent the spread of infection. The wide distribution of melioidosis in tropical Australia and ot ....The bacterium Burkholderia pseudomallei, causes a life threatening condition known as melioidosis. Melioidosis is emerging as an important infectious disease in tropical regions of Australia and South East Asia. Death rates following acute disease are extremely high. Despite the importance of B. pseudomallei in tropical public health, very little is known regarding how the body's defence mechanisms prevent the spread of infection. The wide distribution of melioidosis in tropical Australia and other parts of the world, and the lack of basic scientific information regarding this disease, has prompted this study. The bacterium lives within the body's cells and therefore does not respond well to standard antibiotic treatment. Although some of the basic immune mechanisms have been identified, how protection to the organism develops remains unclear. In this project we will investigate the effect of B. pseudomallei on immune cells or lymphocytes. This study will determine the patients' immune responses to the bacteria causing the disease. Our research team has already successfully carried out work on several different aspects of melioidosis. The characterisation of the basic immune function determined in the proposed study will provide the scientific basis for improvement in treatment and the development of possible preventive strategies against melioidosis.Read moreRead less
Immune Regulation, Cellular Trafficking And Chemokine Receptors In Intestinal Inflammation
Funder
National Health and Medical Research Council
Funding Amount
$204,750.00
Summary
The intestine is exposed to a vast array of foreign substances, or antigens, from food to the abundant bacteria that populate the gut. The gut immune system has developed elaborate and poorly understood mechanisms for preventing inflammation in response to these antigens. A breakdown in these control mechanisms may be partly responsible for the chronic intestinal diseases known as inflammatory bowel diseases, which cause abdominal pain, diarrhoea and bleeding. A recently described immune cell ty ....The intestine is exposed to a vast array of foreign substances, or antigens, from food to the abundant bacteria that populate the gut. The gut immune system has developed elaborate and poorly understood mechanisms for preventing inflammation in response to these antigens. A breakdown in these control mechanisms may be partly responsible for the chronic intestinal diseases known as inflammatory bowel diseases, which cause abdominal pain, diarrhoea and bleeding. A recently described immune cell type, known as a regulatory T cell (T reg), is a powerful candidate cell as a master controller of intestinal inflammation. We know that T cells move to various sites in the body under the influence of hormone-like proteins known as chemokines, but the existence of T reg cells in the intestine, their characteristics, their behaviour and their specific response to chemokines, are all unknown. These studies aim to examine the presence and nature of T reg cells in human and mouse intestine, in both health and inflammation, and to explore how these cells migrate into the gut under the influence of chemokines. This knowledge will help in our understanding of intestinal immunity and endogenous regulation of immune responses, and will provide new targets for treatment of inflammatory bowel disease, and potentially other inflammatory diseases.Read moreRead less