Membrane TNF And Lymphotoxin Control Of Chemokine Induction And Inflammation In Tuberculosis
Funder
National Health and Medical Research Council
Funding Amount
$457,500.00
Summary
Tuberculosis (TB) remains an enormous problem worldwide. Most TB is not due to disease at the time of infection, but is a reactivation of dormant disease in people who have never completely eradicated the organisms. Macrophages containing dormant TB organisms are located in lesions called granulomas. Granulomas consist of TB-infected macrophages surrounded by T lymphocytes that actively contain the infection. T lymphocytes prevent the growth of TB organisms in the macrophages and so prevent wide ....Tuberculosis (TB) remains an enormous problem worldwide. Most TB is not due to disease at the time of infection, but is a reactivation of dormant disease in people who have never completely eradicated the organisms. Macrophages containing dormant TB organisms are located in lesions called granulomas. Granulomas consist of TB-infected macrophages surrounded by T lymphocytes that actively contain the infection. T lymphocytes prevent the growth of TB organisms in the macrophages and so prevent widespread infection that would cause illness in the host. Activated T lymphocytes that recognise TB-infected macrophages circulate in blood, are recruited from blood capillaries into the lung, migrate through the tissue and co-localise with infected macrophages. Soluble molecules (cytokines and chemokines) are known to provide the signals that direct cell migration and activation events. This study will investigate in detail cytokines and chemokines that are involved, the cells that produce then and where these cells are located in the lung. We recently showed that tumour necrosis factor (TNF), and the related cytokine lymphotoxin (LT), are essential for lymphocyte migration through the lung. These belong to a family of related molecules that signal through the same panel of receptors and regulate chemokine expression and inflammation. In this study we will use genetically manipulated mice that lack TNF. LT or other family members or that express only membrane-bound TNF to study how each affects production of different chemokines, chemokine receptors and other molecules. Since there are at least 50 known chemokines and 17 chemokine receptors we will use microarray technology to simultaneously screen changes in expression of several thousand genes and laser microdissection to study cells from different location in infected lungs. Understanding signals necessary to direct T cells into granulomas may facilitate new treatments to prevent TB reactivation disease.Read moreRead less
Cell Migration And Granuloma Formation In The Expression Of Protective Immunity Against Tuberculosis In The Lung
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
Tuberculosis (TB) remains an enormous problem worldwide and a continuing health problem in Australia. Most TB is not due to disease at the time of infection, but is a reactivation of dormant infection in people who have never eradicated the organisms. This study will investigate, in mice, how TB is initially contained within the lungs and how reactivation occurs. All mice infected with TB control the infection initially. T lymphocytes are activated and T cells and macrophages are recruited to th ....Tuberculosis (TB) remains an enormous problem worldwide and a continuing health problem in Australia. Most TB is not due to disease at the time of infection, but is a reactivation of dormant infection in people who have never eradicated the organisms. This study will investigate, in mice, how TB is initially contained within the lungs and how reactivation occurs. All mice infected with TB control the infection initially. T lymphocytes are activated and T cells and macrophages are recruited to the lung, migrate into lung tissue and surround infected lung macrophages forming granulomas. We have identified mice that progress to TB disease early after infection (early progressor strains) and another strain that progresses later (late progressors). In the early progressors, lymphocytes are not as efficiently recruited to the lung and do not form the tight granulomas seen in late progressor strains. We plan to make a detailed comparison of these two strains looking at differences in cell-membrane molecules and the soluble messenger molecules (cytokines and chemokines) that provide the signals that attract cells to the lung and direct them to surround infected lung macrophages. By comparing events in early and late progressor strains we will find which molecules are required for initial and long-term containment, and which events lead to breakdown of granulomas and reactivation of disease. In addition, we recently showed that one cytokine, tumour necrosis factor (TNF), is essential for cell migration through the lung. By comparing normal mice with mice deficient in TNF we will study the downstream effects regulated by TNF, particularly the chemokine messengers that direct cell movement into granulomas. By identifying the molecules and cells required to control TB we plan to design improved vaccines to prevent TB infection and improved treatments to prevent disease reactivation.Read moreRead less
Cytokine And Macrophage Determinants Of Pulmonary Inflammation During Tuberculosis
Funder
National Health and Medical Research Council
Funding Amount
$455,899.00
Summary
Tuberculosis (TB) infects 33% of the world, causing over 2 million deaths per year. TB disease causes damaging lung pathology and new therapies to treat the infection and moderate inflammation are urgently required. TNF is essential for immunity to TB, acting to modulate inflammation. This grant will determine how soluble and membrane- bound TNF regulate the cellular and cytokine control of TB pathology and may lead to new therapies to limit inflammation in TB and other inflammatory diseases.
Genetic Adaptations Of Mycobacterium Tuberculosis For Intracellular Survival
Funder
National Health and Medical Research Council
Funding Amount
$187,677.00
Summary
Tuberculosis (TB) remains a significant global public health problem and new approaches to its treatment and prevention are urgently needed. The disease is caused by infection with Mycobacterium tuberculosis, a slow growing organism that lives within cells. How it adapts to survive in this intracellular environment is unknown. Recently the complete genome of M. tuberculosis was sequenced and new techniques developed for manipulating its genes. We plan to use these techniques to identify genes th ....Tuberculosis (TB) remains a significant global public health problem and new approaches to its treatment and prevention are urgently needed. The disease is caused by infection with Mycobacterium tuberculosis, a slow growing organism that lives within cells. How it adapts to survive in this intracellular environment is unknown. Recently the complete genome of M. tuberculosis was sequenced and new techniques developed for manipulating its genes. We plan to use these techniques to identify genes that are more active within the cells. Genes are controlled by short sequences of preceding DNA called promoters. If these promoters are randomly placed in front of readily identifiable reporter genes and inserted into a suitable host strain, it is possible to select for those promoters expressed only inside cells and then identify the promoter and its gene by sequence analysis. We plan to use two types of reporter genes. First, we shall place the M. tuberculosis DNA containing promoters before the gene for a naturally fluorescent protein within the M. bovis BCG host strain and then infect macrophages. If the promoters are switched on inside the cell, the macrophages will become green and can be selected and the promoter identified. After several rounds of selection the promoter is isolated and identified. Second, we shall select the promoters by their ability to produce a protein that is on the surface of the bacterium. We will use these intracellular genes to make better vaccines against TB. Genes that enhance intracellular survival may contribute to the virulence of the TB organism. By removing these genes we can make an attenuated organism suitable as a vaccine. We will test for reduced virulence by growth inside cells in mice. We will also use the intracellular promoter to improve the current BCG vaccine. Proteins expressed inside the cell may also be targets for new TB drugs.Read moreRead less
Dissecting In Vivo Cellular Responses To Interferons In Pathogen-infected Hosts
Funder
National Health and Medical Research Council
Funding Amount
$479,694.00
Summary
Tuberculosis (TB) is caused by virulent bacterium Mycobacterium tuberculosis and is a leading cause of death worldwide. Mechanisms underlying host resistance to the pathogen are poorly understood. Using a novel reporter mouse, the function of interferons in Mtb infection will be defined in vivo by tracking the cytokine-responsive cells. This will increase our understanding of the effects of these important cytokines in vivo, and could provide new candidate biomarkers for TB diagnosis.
Improved Vaccines Against Tuberculosis Based On Dendritic Cell Manipulation
Funder
National Health and Medical Research Council
Funding Amount
$257,036.00
Summary
The incidence of tuberculosis (TB) is increasing throughout the world. BCG, the only currently available vaccine is only partially protective and better vaccines are urgently required to help limit the spread of TB. We have recently prepared naked DNA vaccines with the genes for three mycobacterial proteins and found that they partially protected against lung TB in mice. Further improvement is required and this project is to design and test improved DNA vaccines. Vaccines will be more effective ....The incidence of tuberculosis (TB) is increasing throughout the world. BCG, the only currently available vaccine is only partially protective and better vaccines are urgently required to help limit the spread of TB. We have recently prepared naked DNA vaccines with the genes for three mycobacterial proteins and found that they partially protected against lung TB in mice. Further improvement is required and this project is to design and test improved DNA vaccines. Vaccines will be more effective if they generate stronger cellular immune response to mycobacteria. Dendritic cells (DC) are the major cells that present mycobacterial antigens to T lymphocytes and thus stimulate T lymphocytes to generate immune responses that protect against TB. Therefore the aim of this project is to identify ways to manipulate DC to improve their ability to activate protective immunity. We will target membrane molecules on DC to activate the antigen- presenting function of these cells by fusing the genes for mycobacterial proteins to genes either for antibodies to surface molecules on DC or receptors for these molecules. These novel DNA vaccines will be tested for their effects on DC function and their capacity to stimulate the protective pattern of immunity in mice. The cytokine environment at the time of stimulation will be modified by giving the DNA vaccine together with two cytokine-expressing vaccines, to 'push' the T lymphocytes to respond more vigorously. Finally, we shall test whether a combination of the new DNA vaccines and BCG is more effective than BCG at protecting against virulent TB infection.Read moreRead less
Translating Respiratory And Environmental Epidemiology Into Improved Lung Health
Funder
National Health and Medical Research Council
Funding Amount
$319,714.00
Summary
Chronic respiratory disease, tuberculosis and the effects of air pollution are important health problems globally. Evaluating current approaches to dealing with these problems and developing new approaches requires good data. Over the next five years I will lead a number of studies addressing these issues, in Australia and internationally, in order to provided the strongest possible evidence to underpin policy.
IMPROVING PULMONARY TUBERCULOSIS (TB) OUTCOMES: Investigating Novel Adjunctive Immunotherapies And Addressing HIV-TB Co-infection In Papua, Indonesia
Funder
National Health and Medical Research Council
Funding Amount
$217,846.00
Summary
Tuberculosis remains a major regional and global problem, especially in resource-limited settings such as Australia’s northern neighbours. Three key challenges are to make TB cure easier by shortening treatment, improve HIV-TB co-infection management, and tackle drug resistance. We address these issues in Indonesia’s Papua Province, where we are testing whether simple supplements given with TB treatment might accelerate cure; improving HIV care in people with TB, and detecting drug-resistant TB.
I aim to use high-quality laboratory science, clinical and social research, and strong public health principles, to address the major health problems of the Asia-Pacific region and improve health through translatable outcomes