A New Model For The Pathogenesis Of Rheumatic Fever: Superantigen Priming Of The Immune Response To Group A Streptococci
Funder
National Health and Medical Research Council
Funding Amount
$248,820.00
Summary
Acute rheumatic fever (ARF) is now rare in developed countries. However, it remains a major problem in Aboriginal Australians in the NT where the rate of ARF is the highest in the world. This leads to high rates of rheumatic heart disease (up to 3% of individuals in some communities) and a premature mortality of over four times that for developing countries. Immunisation and improved living conditions offer a long-term solution but these remain a distant prospect. In the short and medium term, c ....Acute rheumatic fever (ARF) is now rare in developed countries. However, it remains a major problem in Aboriginal Australians in the NT where the rate of ARF is the highest in the world. This leads to high rates of rheumatic heart disease (up to 3% of individuals in some communities) and a premature mortality of over four times that for developing countries. Immunisation and improved living conditions offer a long-term solution but these remain a distant prospect. In the short and medium term, control of this ARF will partly depend on new and better treatment and prevention strategies. To achieve these goals a deeper understanding of the immune mechanisms underlying this disease is urgently needed. It is known that ARF is caused by an abnormal immune response following streptococcal infection. This leads to the production of cells called T cells that attack the body s own tissues rather than the bacteria itself. This autoimmune disease is responsible for the heart damage that underlies ARF. It is believed that this proces only occurs when susceptible individuals are infected with specific rheumatogenic strains of streptococci. However there are a number of deficiencies in this model and it is proposed that there is an additional factor responsible for the abnormal immune response in ARF. This project will explore the possibility that bacterial toxins called superantigens are the critical missing factor , by studying the immune response in ARF. Superantigens are produced by certain streptococci and staphylococci, and are potent in minute quantities causing widespread activation of the immune system. They have been found to play an important role in a number of autoimmune diseases and the type of immune response found in ARF fits well with that expected if superantigens were involved. If superantigens play an important role in causing the abnormal immune response in ARF then a number of new avenues would open for the treatment and prevention of this disease.Read moreRead less
Mathematical Modelling Of Bacterial Carriage In Children
Funder
National Health and Medical Research Council
Funding Amount
$421,746.00
Summary
Children exposed to larger numbers of other children are at risk of persistent bacterial infections. Such circumstances explain the high rates of ear and chest infections, and skin sores seen in children in historical times. Changing social circumstances (smaller families, better housing, nutrition and hygiene), as well as the introduction of antibiotics, explain the decline of such infections in affluent communities since the early 20th century. However, even today, in affluent countries, child ....Children exposed to larger numbers of other children are at risk of persistent bacterial infections. Such circumstances explain the high rates of ear and chest infections, and skin sores seen in children in historical times. Changing social circumstances (smaller families, better housing, nutrition and hygiene), as well as the introduction of antibiotics, explain the decline of such infections in affluent communities since the early 20th century. However, even today, in affluent countries, children attending group child care are at high risk of ear infections. As many bacteria are resistant, antibiotics are now much less effective than when they were first introduced. Furthermore, there is a continuing load of infection for children in Aboriginal communities, in PNG and other developing countries, causing hearing loss, chronic respiratory problems, and heart disease and renal disease in later life. Using data previously collected from other studies in Indigenous communities and children in child care, mathematical models allow us to ask what if?, and answer important public health questions: 1. What environmental and public health measures can reduce the cycle of cross-infection in child-care and high-risk populations? 2. What coverage rates with pneumococcal vaccine will eliminate the vaccine-specific bacteria from child care centres, from the wider community, and from high risk populations? 3. Will infections with bacteria not covered by vaccine then increase? 4. Will the resistant bacteria tend to disappear if antibiotic use is restricted? 5. Under what circumstances will antibiotics help to control infection? The modelling will promote understanding of the social and health costs of bacterial infection in Aboriginal communities and child care and use educational scenarios to promote uptake of the most cost-effective and socially acceptable interventions.Read moreRead less
Alcoholic Chronic Pancreatitis: Induction, Progression And Reversal
Funder
National Health and Medical Research Council
Funding Amount
$632,211.00
Summary
Pancreatitis (inflammation of the pancreas) is a serious complication of alcohol abuse. Patients suffer from severe and often intractable abdominal pain, maldigestion and diabetes, We have recently shown that gut toxins (endotoxins) may act as a trigger factor for pancreatitis in alcoholics. The proposed project aims to characterise the effects of gut toxins on the pancreas during alcohol abuse so as to identify pathways that may be therapeutically targeted to prevent or retard the disease.
A Randomised Trial To Control Sexually Transmitted Infections In Remote Aboriginal Communities.
Funder
National Health and Medical Research Council
Funding Amount
$1,847,403.00
Summary
This project will trial strategies for attaining clinical best practice in sexual health with an overall objective of reducing the high rates of sexually transmitted infection in remote Aboriginal communities in central and northern Australia. The trial will take place in 21 communities of which seven will be randomly assigned in each of the three years of the trial. This trial will determine whether strengthening primary health services can reduce the level of these infections.
Regulation Of Secretion Of The Fungal Virulence Determinant, Phospholipase B
Funder
National Health and Medical Research Council
Funding Amount
$487,500.00
Summary
Serious systemic infections due to fungi have increased dramatically in the past few years, especially in people with poorly functioning immune systems. Treatment of these conditions is problematic because the few drugs which are available are not highly effective, and-or cause significant side-effects. Little is understood of how fungi cause disease, and this problem must be addressed if these infections are to be contained. We have discovered that the enzyme, phospholipase B (PLB), is secreted ....Serious systemic infections due to fungi have increased dramatically in the past few years, especially in people with poorly functioning immune systems. Treatment of these conditions is problematic because the few drugs which are available are not highly effective, and-or cause significant side-effects. Little is understood of how fungi cause disease, and this problem must be addressed if these infections are to be contained. We have discovered that the enzyme, phospholipase B (PLB), is secreted by the disease-causing fungus, Cryptococcus neoformans, and that it is important in enabling the fungus to invade the host's cells and spread around the body from the lungs to the brain, where it can cause meningoencephalitis. PLB is also produced by other disease-causing fungi. The mechanism of PLB secretion is completely unknown. In this project we aim to determine the pathways involved in PLB secretion with the intention of exploiting steps unique to pathogenic fungi, for the future design of new anti-fungal drugs.Read moreRead less
Analysis Of Viral And Cellular Gene Expression During Human Cytomegalovirus Latent Infection Of Hematopoietic Cells
Funder
National Health and Medical Research Council
Funding Amount
$407,545.00
Summary
Human cytomegalovirus (HCMV) is a herpesvirus which infects a majority of the population. HCMV is a significant cause of serious, life-threatening disease in neonates and in people who are immunosuppressed. Transplant recipients such as bone marrow, kidney and heart transplant patients are particularly at risk of developing HCMV disease. Like other herpesviruses, after initial infection HCMV can establish a life-long latent infection. During latency, the virus remains dormant in the human body a ....Human cytomegalovirus (HCMV) is a herpesvirus which infects a majority of the population. HCMV is a significant cause of serious, life-threatening disease in neonates and in people who are immunosuppressed. Transplant recipients such as bone marrow, kidney and heart transplant patients are particularly at risk of developing HCMV disease. Like other herpesviruses, after initial infection HCMV can establish a life-long latent infection. During latency, the virus remains dormant in the human body and no infectious virus is made. However, when conditions are right the virus can awaken (ie reactivate) from its latent state, producing new infectious virus and disease. It is in immunosuppressed individuals such as transplant patients that viral latency and reactivation are of most medical concern, yet viral latency remains very poorly understood. This project has three major components. Firstly, we aim to continue studies which are defining what viral genes are active (ie expressed) during latent infection. Identification of these genes and determination of how they function may have profound implications to our understanding of latency. Secondly, we will examine how human cells are affected when they become latently infected. A new and exciting technology called DNA microarray now makes it possible to examine the expression of many thousands of genes in a single experiment. For the first time, we will be able to determine how the cell changes during latency and reactivation. The study of viral and cellular gene expression during latency may contribute to the development of drugs which interfere with the viruses ability to become latent or reactivate. Thirdly, we have preliminary results which suggest that latent HCMV may actively avoid detection by the immune system. In this project we also aim to determine the mechanism by which the virus interferes with the expression of molecules which are an essential component of our immune system.Read moreRead less
Molecular Mechanisms Of Varicella Zoster Virus Interactions With Key Target Cells
Funder
National Health and Medical Research Council
Funding Amount
$421,650.00
Summary
Varicella zoster virus (VZV) is a herpesvirus which infects up to 90% of the population. VZV causes chickenpox (varicella) predominantly in childhood and shingles (herpes zoster) in middle to old age people. Whilst VZV usually causes relatively mild disease in healthy individuals, VZV still causes significant morbidity in children and adults. VZV causes life-threatening disease in immunocompromised individuals such as patients who are elderly or have HIV disease . Herpes zoster affects many eder ....Varicella zoster virus (VZV) is a herpesvirus which infects up to 90% of the population. VZV causes chickenpox (varicella) predominantly in childhood and shingles (herpes zoster) in middle to old age people. Whilst VZV usually causes relatively mild disease in healthy individuals, VZV still causes significant morbidity in children and adults. VZV causes life-threatening disease in immunocompromised individuals such as patients who are elderly or have HIV disease . Herpes zoster affects many ederly individuals and a major complication is prolonged severe pain or post-herpetic neuralgia (PHN), both severely debilitating and which often requires follow-up medical care for months or years after the initial attack. Despite its significant impact on the community, little is known about the molecular details of how this virus functions. This project aims to improve our understanding of how VZV infection affects specialised human cells in order to make further advances in antiviral therapies as well improve vaccine design for the treatment or prevention of VZV disease and the crippling complication of PHN. This project has four components: (1) We will continue studies which have shown that VZV may actively avoid detection by the immune system. We aim to identify the mechanism and viral genes responsible for interfering with the expression of molecules which are essential for our immune system. (2) We will determine whether VZV infection of specialised immune cells (called dendritic cells) will affect their ability to function and interact with other immune cells (called T cells). (3) We will examine how VZV interacts in human nerve cells (neurons) and whether infected neurons undergo specially programmed cell death (apoptosis). (4) We will examine how different human cells change when they are infected with VZV. A new and exciting technology called DNA microarray now makes it possible to examine the expression of many thousands of genes in one experiment.Read moreRead less
Invasive fungal infections are a serious, escalating health issue. They cause severe disease with high death rates and are very costly to the health system. Current drugs often have suboptimal efficacy and cause side effects. New drugs are needed urgently. Many fungi, including the AIDS-related pathogen, Cryptococcus neoformans, secrete phospholipase B (Plbp) to facilitate infection. We will identify and investigate the Plbp secretion pathway as a novel anti-fungal drug target.