Apoptosis Amongst Specific And Bystander T Cells In Chronic Bacterial Infection
Funder
National Health and Medical Research Council
Funding Amount
$317,545.00
Summary
When an infection occurs the immune cells (lymphocytes) proliferate in order to initiate and expand the immune response. If the body had no mechanisms to limit proliferation, the numbers of cells would soon overwhelm the body. Working with simple protein antigens rather than infection, other workers have found that once T lymphocytes have been activated and the immune response triggered, they soon undergo a process of self destruction called apoptosis. However, during infection, if the limits to ....When an infection occurs the immune cells (lymphocytes) proliferate in order to initiate and expand the immune response. If the body had no mechanisms to limit proliferation, the numbers of cells would soon overwhelm the body. Working with simple protein antigens rather than infection, other workers have found that once T lymphocytes have been activated and the immune response triggered, they soon undergo a process of self destruction called apoptosis. However, during infection, if the limits to lymphocyte proliferation are imposed before the infecting bacterium is eliminated, full expression of immunity does not occur and chronic infection may result. We believe that this contributes to the chronicity of such infections as tuberculosis and leprosy. We also suspect that, during infection, not only protective T lymphocytes proliferate, but also nonspecific bystander cells. This exaggerates the problem of lymphocyte proliferation and adds to immunopathology (immune damage). We have established an animal model of chronic bacterial infection in order to study how apoptosis is induced in T lymphocytes and how its adverse effects may be overcome. We hypothesize that apoptosis may be induced by one or more of a number of mechanisms, and that they may differ for the specific protective cells and the bystander cells. Once we understand the mechanisms apoptosis of specific lymphocytes may be prevented without harming the body. This has the potential to open new areas of immunotherapy (manipulating the immune response) of these diseases.Read moreRead less
The Role Of Interferon Gamma And Nitric Oxide As Downregulating Molecules In Central Nervous System Inflammation
Funder
National Health and Medical Research Council
Funding Amount
$526,644.00
Summary
Cytokines are soluble factors which participate in inflammatory responses. Interferon gamma is a cytokine which in the context of central nervous system inflammation has been considered a Obad? molecule, as has the gas nitric oxide which is induced by interferon gamma. We now have direct evidence that indicate quite the contrary, ie interferon gamma and nitric oxide can a do act as down regulators of inflammation. The present work is designed to determine if this down regulating function is rest ....Cytokines are soluble factors which participate in inflammatory responses. Interferon gamma is a cytokine which in the context of central nervous system inflammation has been considered a Obad? molecule, as has the gas nitric oxide which is induced by interferon gamma. We now have direct evidence that indicate quite the contrary, ie interferon gamma and nitric oxide can a do act as down regulators of inflammation. The present work is designed to determine if this down regulating function is restricted only to a single model of CNS inflammation or is a general phenomenon within the CNS. The project will also involve a number of experiments designed to elucidate the mechanism(s) by which down regulation occurs. This project is highly significant in that a single uncontrolled clinical trial of interferon gamma for the therapy of MS has been carried out and reported as indicating that interferon gamma made the disease worse. The design of that trial however was such that the validity of that claim is questionable. If our experiments confirm the general nature of interferon gamma as a down regulator in inflammation in a number of different models of MS then a case for revisiting the use of interferon, or a downstream product of interferon, in the therapy of MS might be made.Read moreRead less
Cellular And Molecular Mechanisms Of Transcutaneous Immunisation
Funder
National Health and Medical Research Council
Funding Amount
$190,490.00
Summary
Vaccines are among the most effective medical interventions. The recent discovery that cholera toxin, when applied to the normal skin of humans and laboratory animals, stimulates powerful and protective immune responses to itself, and to other proteins has opened up the possibility of needle-free vaccines in the form of skin patches. How CT brings about this effect is currently unknown. We have discovered that the immune stimulating effect of CT depends upon the production of an immune protein ( ....Vaccines are among the most effective medical interventions. The recent discovery that cholera toxin, when applied to the normal skin of humans and laboratory animals, stimulates powerful and protective immune responses to itself, and to other proteins has opened up the possibility of needle-free vaccines in the form of skin patches. How CT brings about this effect is currently unknown. We have discovered that the immune stimulating effect of CT depends upon the production of an immune protein (cytokine) called tumour necrosis factor (TNF). TNF is known to activate specialised immune cells within the skin (Langerhan's Cells ) and we hypothesise that the interaction beween CT and LC via TNF is the pathway to the potent immune response. In this project we propose to investigate the cells and molecules involved in the immune effects of CT in the skin with a view to the development of new skin based vaccine strategies.Read moreRead less
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 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