The Roles Of Lipoprotein Multigene Families In Pathogenesis Of Mycoplasma Pneumoniae
Funder
National Health and Medical Research Council
Funding Amount
$257,036.00
Summary
Mycoplasma pneumoniae is one of the most common causes of community acquired pneumonia. Although it can usually be successfully treated with antibiotics, it can result in more severe diseases and can be difficult to diagnose accurately. It has been identified as a target for vaccine development, but this has been hampered by the limited understanding we have of how it causes disease. The attempts at vaccination that have been made have resulted in vaccines which induced more severe, rather than ....Mycoplasma pneumoniae is one of the most common causes of community acquired pneumonia. Although it can usually be successfully treated with antibiotics, it can result in more severe diseases and can be difficult to diagnose accurately. It has been identified as a target for vaccine development, but this has been hampered by the limited understanding we have of how it causes disease. The attempts at vaccination that have been made have resulted in vaccines which induced more severe, rather than less severe, disease. Investigations of several other related bacteria have shown that they are able to vary their surface proteins and thus may evade the immune system, permitting them to cause more prolonged disease. Better understanding how this occurs, and what this enables the bacteria to do, may assist in developing improved vaccine strategies. This project aims to investigate the six gene families in Mycoplasma pneumoniae which are known to encode surface proteins and establish how and why the bacteria switch from one gene to another during infection. In addition the capacity of bacteria expressing different versions of the six surface proteins to adhere to different tissues will be investigated. Once this is known, these mechanisms may be able to be specifically disrupted to prevent a strain of Mycoplasma pneumoniae from being able to establish prolonged infections. Such a strain might be a useful basis for an effective vaccine.Read moreRead less
Investigation Of The Association Between Chlamydial Infection And Asthma In Different Age Groups
Funder
National Health and Medical Research Council
Funding Amount
$382,117.00
Summary
Asthma is a common and severe lung disease that results from inflammation due to allergy and has symptoms of breathing difficulties, wheezing, chest tightness, and cough. Asthma is clinically characterised by the presence of certain types of responses from the immune system. We are looking for ways of preventing and curing asthma. There is a well known link between certain types of bacteria, called Chlamydia, and asthma but it is not known whether people develop asthma first and then get chlamyd ....Asthma is a common and severe lung disease that results from inflammation due to allergy and has symptoms of breathing difficulties, wheezing, chest tightness, and cough. Asthma is clinically characterised by the presence of certain types of responses from the immune system. We are looking for ways of preventing and curing asthma. There is a well known link between certain types of bacteria, called Chlamydia, and asthma but it is not known whether people develop asthma first and then get chlamydial infection or are infected first and this leads to asthma. We have shown that if adult mice are exposed to an allergen during chlamydial infection then the asthma gets worse. However, if newborn mice have a chlamydial infection then asthma is prevented when they are adults. These are preliminary observations, which we need to expand and understand the immune mechanisms that result in infection and allergy so that we can target them with antibiotics or vaccines. We will investigate how the timing of chlamydial infection relative to exposure to allergens (before, during or after) affects the development of asthma in adult mice. Newborns and young children have different immune systems to adults, so we will investigate what effects the infection of young mice has on infection and allergy later in life. We will also test a new vaccine we have developed against chlamydial infection to see if it can prevent chlamydial infection and infection-induced asthma. We will then examine if there is the same association between chlamydial infection and asthma in human asthmatics that present to hospital with exacerbation of their asthma. This work will help us develop new strategies for preventing and curing asthma, which may vary in different age groups. We will identify whether prevention of chlamydial infection by vaccination (or antibiotics) can be used to prevent and treat asthma.Read moreRead less
Intracellular Survival Of Burkholderia Pseudomallei And Evasion Of Autophagy
Funder
National Health and Medical Research Council
Funding Amount
$450,799.00
Summary
Melioidosis is a disease with high mortality that is caused by the bacterium Burkholderia pseudomallei. Autophagy is a natural part of the mammalian immune system. This project seeks to explain how Burkholderia pseudomallei avoids killing by host autophagy and identify the bacterial factors necessary for its survival within cells. The identified genes will be future targets for medical intervention.
The Intracellular Replicative Niche Of Legionella Species And Coxiella Burnetii.
Funder
National Health and Medical Research Council
Funding Amount
$529,632.00
Summary
This project will study how the bacterium that causes Legionnaire's disease survives and grows inside human cells. We have identified new bacterial proteins that allow Legionella to manipulate the normal host cell processes involved in killing an invading bacterium. Similar proteins are also present in the closely related organism, Coxiella, which causes Q-fever. By determining how these proteins act, this work may result in new treatments for Legionnaire's disease and related infections.
GENETIC ANALYSIS OF POLYSACCHARIDE CAPSULE BIOSYNTHESIS AND REGULATION IN STREPTOCOCCUS PNEUMONIAE
Funder
National Health and Medical Research Council
Funding Amount
$377,036.00
Summary
Streptococcus pneumoniae (the pneumococcus) is an important cause of invasive diseases such as pneumonia, meningitis and bacteraemia in humans. Many people carry this organism in the nasopharynx asymptomatically. However, in a small proportion, the organism overcomes host defences and invades the body causing life-threatening disease. An essential virulence factor of the pneumococcus is the polysaccharide capsule which protects it from the immune defences of the host during an infection. Until r ....Streptococcus pneumoniae (the pneumococcus) is an important cause of invasive diseases such as pneumonia, meningitis and bacteraemia in humans. Many people carry this organism in the nasopharynx asymptomatically. However, in a small proportion, the organism overcomes host defences and invades the body causing life-threatening disease. An essential virulence factor of the pneumococcus is the polysaccharide capsule which protects it from the immune defences of the host during an infection. Until recently, very little was known of the pneumococcal genes involved in production of this antigen. This project aims to continue characterization of these genes, and examination of the factors which regulate their expression. This regulatory mechanism may be very important, because production of increased levels of the polysaccharide capsule is believed to be an crucial step in the transition from carriage to invasion. An understanding of the molecular events involved in biosynthesis and regulation of capsule production will improve our understanding of the disease process and identify alternative targets for antimicrobial therapy.Read moreRead less
MOLECULAR ANALYSIS OF VIRULENCE FACTORS OF GROUP B STREPTOCOCCI
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
Streptococcus agalactiae, more commonly referred to as group B streptococcus (GBS), is the commonest cause of life-threatening infection (specifically bacteraemia, pneumonia and meningitis) in neonates. Mortality is high even in developed countries where antimicrobial therapy is readily available. In spite of the importance of GBS disease, the precise molecular mechanisms whereby the organism colonizes, invades and damages host tissues are poorly understood. The long term goal of this project is ....Streptococcus agalactiae, more commonly referred to as group B streptococcus (GBS), is the commonest cause of life-threatening infection (specifically bacteraemia, pneumonia and meningitis) in neonates. Mortality is high even in developed countries where antimicrobial therapy is readily available. In spite of the importance of GBS disease, the precise molecular mechanisms whereby the organism colonizes, invades and damages host tissues are poorly understood. The long term goal of this project is to gain a complete understanding of the pathogenesis of GBS disease and to apply this to development of improved preventative strategies. We propose to carry out a comprehensive molecular characterization of genes encoding putative GBS virulence determinants, with particular reference to those which encode the capacity to adhere to and invade host cells. GBS carrying defined mutations in these genes will be constructed and their virulence will be compared with that of the otherwise isogenic parental GBS. This will enable us to determine the precise contribution of each putative virulence factor to the pathogenesis of disease. Moreover, proteins shown to be important in this process will be tested for vaccine potential.Read moreRead less
Streptococcus pneumoniae (the pneumococcus) is an important human pathogen, which is responsible for the deaths of millions of children each year in developing countries. The high morbidity and mortality associated with pneumococcal disease is also being exacerbated by the rate at which this organism is acquiring resistance to multiple antibiotics. Existing pneumococcal polysaccharide vaccines are poorly immunogenic in young children and only provide cover against a limited range of serotypes. S ....Streptococcus pneumoniae (the pneumococcus) is an important human pathogen, which is responsible for the deaths of millions of children each year in developing countries. The high morbidity and mortality associated with pneumococcal disease is also being exacerbated by the rate at which this organism is acquiring resistance to multiple antibiotics. Existing pneumococcal polysaccharide vaccines are poorly immunogenic in young children and only provide cover against a limited range of serotypes. Serotype coverage is even lower in the more immunogenic conjugate vaccines currently being developed; these will also be very expensive, thereby limiting their use in developing countries, where the need for effective paediatric vaccines is greatest. Pneumococci produce a variety of proteins which are important in causing disease, but the relative contribution of these factors at each stage of the infection process remain to be determined. Moreover, virtually nothing is known of the mechanism whereby these virulence factors are regulated in response to the external environment of the bacterium. In view of this, we are conducting a comprehensive examination of the mechanisms of pathogenesis of pneumococcal disease, with particular reference to the role of putative virulence proteins. This information is being used to develop cheap and effective vaccines based on pneumococcal protein antigens common to all serotypes.Read moreRead less