Role In Disease And Vaccine Potential Of Cell Surface O-linked Glycoproteins In Pathogenic Neisseria.
Funder
National Health and Medical Research Council
Funding Amount
$212,347.00
Summary
Bacteria that have adapted to life exclusively in the human host have developed unique strategies to colonize the host and to evade the immune response. An emerging strategy is modification of bacterial surface proteins with sugars or other modifications. Our data suggests a key role for these modifications in disease. We will investigate how the modifications are made, discover structures of novel modifications and determine their precise role in disease.
Some bacteria can cause inflammation of the brain (bacterial meningitis). This leads to 170,000 deaths annually in the world. Many patients who survive after antibiotic treatment have lifelong disabilities like deafness, and problems of memory and learning. We aim to show that a certain biochemical pathway in the brain contributes to death and disability, with a view to identifying new drug treatments that can be used alongside antibiotics to improve disease outcomes.
Certain bacterial DNA repeats are prone to hyper mutation. Genes with these repeats, Contingency genes, are randomly switched on and off. This process, phase variation , generates diversity in a population. Recently we described a new class of contingency gene that methylates DNA. On-off switching of this gene leads to random switching of multiple genes; the phasevarion . We will define the impact of this system in bacteria causing meningitis and STDs.
Cryptococcal Meningoencephalitis - Fungal Determinants Of Invasion Of The CNS
Funder
National Health and Medical Research Council
Funding Amount
$587,634.00
Summary
Meningitis and brain infection (meningoencephalitis) due to the fungus Cryptococcus, affect over 1 million patients with AIDS annually, especially in developing countries; with more than 600,000 deaths. It is not known how Cryptococci cross from the blood stream into the brain; this must be elucidated in order to prevent and/or control this devastating infection. This project will determine how cryptococci influence host blood cells to act as “Trojan horses” and/or release products that initiate ....Meningitis and brain infection (meningoencephalitis) due to the fungus Cryptococcus, affect over 1 million patients with AIDS annually, especially in developing countries; with more than 600,000 deaths. It is not known how Cryptococci cross from the blood stream into the brain; this must be elucidated in order to prevent and/or control this devastating infection. This project will determine how cryptococci influence host blood cells to act as “Trojan horses” and/or release products that initiate invasion of brain tissue and meningitis.Read moreRead less
The Role Of Lipooligosaccharide Phosphoethanolamine Transferases In The Pathogenesis Of Neisseria Meningitidis And N. Gonorrhoeae
Funder
National Health and Medical Research Council
Funding Amount
$574,890.00
Summary
Neisseria meningitidis is the causative agent of meningococcal disease, a rapidly transmissible form of fatal sepsis. The related pathogen, N. gonorrhoeae, causes the sexually transmitted gonorrhoeae and is implicated in the loss of fertility in 10% of patients. This project will analyse the function of a protein necessary for the ability of the both pathogens to cause disease. We will further characterize the function of this protein and determine whether it is a viable candidate for the develo ....Neisseria meningitidis is the causative agent of meningococcal disease, a rapidly transmissible form of fatal sepsis. The related pathogen, N. gonorrhoeae, causes the sexually transmitted gonorrhoeae and is implicated in the loss of fertility in 10% of patients. This project will analyse the function of a protein necessary for the ability of the both pathogens to cause disease. We will further characterize the function of this protein and determine whether it is a viable candidate for the development of drug therapy.Read moreRead less
Regulatory Networks Controlling Virulence In Neisseria Gonorrhoeae And Neisseria Meningitidis.
Funder
National Health and Medical Research Council
Funding Amount
$300,773.00
Summary
Bacteria that cause disease produce substances called virulence determinants, often on their cell surface. These virulence determinants are either directly involved in allowing infection to take place, or cause the damage that we recognize as an infectious disease. Some virulence determinants are produced all the time, while others are only made in particular conditions - their expression is regulated. To target efforts in the development of new vaccines and treatments, it is important to identi ....Bacteria that cause disease produce substances called virulence determinants, often on their cell surface. These virulence determinants are either directly involved in allowing infection to take place, or cause the damage that we recognize as an infectious disease. Some virulence determinants are produced all the time, while others are only made in particular conditions - their expression is regulated. To target efforts in the development of new vaccines and treatments, it is important to identify all the virulence determinants produced by a particular bacterial species, but also to know which are regulated, and the environmental signals that determine their expression. It can be just as important to know whether a virulence determinant is constantly expressed, and therefore represents an invariant target. Neisseria gonorrhoeae and Neisseria meningitidis are two important disease-causing bacteria that exclusively infect humans and cause gonorrhoea, and meningitis. The complete DNA sequence of both of these bacteria is currently being determined. From computer analysis of these data, it appears that these bacteria have few of the specific regulatory systems that are present in other bacteria. The availability of DNA sequencing data enables an alternative and much more systematic approach to the identification and study of the regulation of virulence determinants. Because of the limited repertoire of regulatory systems still present in N. gonorrhoeae and N. meningitidis, it is feasible to mutate each and determine which are involved in regulation of virulence determinants. We will also be able to identify genes regulated by each system, determine how regulation is achieved, and use this information to identify any presently unknown virulence genes controlled by the same system. Such an analysis has never been previously achieved for any bacterial species, because of the number and complexity of the regulatory systems usually present.Read moreRead less
Regulatory Networks Controlling Virulence In Neisseria Gonorrhoeae And Neisseria Meningitidis.
Funder
National Health and Medical Research Council
Funding Amount
$147,500.00
Summary
Bacteria that cause disease produce substances called virulence determinants, often on their cell surface. These virulence determinants are either directly involved in allowing infection to take place, or cause the damage that we recognize as an infectious disease. Some virulence determinants are produced all the time, while others are only made under particular conditions, that is, their expression is regulated. To target efforts in the development of new vaccines and treatments, it is importan ....Bacteria that cause disease produce substances called virulence determinants, often on their cell surface. These virulence determinants are either directly involved in allowing infection to take place, or cause the damage that we recognize as an infectious disease. Some virulence determinants are produced all the time, while others are only made under particular conditions, that is, their expression is regulated. To target efforts in the development of new vaccines and treatments, it is important to identify all the virulence determinants produced by a particular bacterial species, but also to know which are regulated, and the environmental signals that determine their expression. Neisseria gonorrhoeae and Neisseria meningitidis are two important disease-causing bacteria that exclusively infect humans and cause gonorrhoea, and meningitis. The complete DNA sequence of both of these bacteria is now known. From computer analysis of these data, it appears that these bacteria have few of the specific regulatory systems that are present in other bacteria. Because of the limited repertoire of regulatory systems still present in N. gonorrhoeae and N. meningitidis, it is feasible to mutate each one and determine which are involved in regulation of virulence determinants. We have made copies of every individual gene found in the DNA sequence of these bacteria and have attached each one individually to a glass slide to form a microarray measuring 18mm x 18mm. This microarray will allow us to monitor the expression of every gene in these bacteria in response to environmental signals. This information will be used to identify all the virulence genes controlled by each regulatory system. Such an analysis has never been previously achieved for any bacterial species, because of the number and complexity of the regulatory systems usually present.Read moreRead less
A Study To Investigate Alternative Regimens For Pneumococcal Vaccination Of Infants In A Developing Country
Funder
National Health and Medical Research Council
Funding Amount
$1,622,210.00
Summary
Streptococcus pneumoniae (Pnc) is the leading vaccine preventable cause of serious infection in infants. The current Pnc conjugate vaccine is very expensive (approximately USD $200-infant) so it is unlikely to be affordable for most developing countries. Moreover, as health care access in developing countries may be episodic and unreliable, many children do not receive either complete or timely vaccine courses. Therefore, it is important to investigate affordable and flexible ways to deliver thi ....Streptococcus pneumoniae (Pnc) is the leading vaccine preventable cause of serious infection in infants. The current Pnc conjugate vaccine is very expensive (approximately USD $200-infant) so it is unlikely to be affordable for most developing countries. Moreover, as health care access in developing countries may be episodic and unreliable, many children do not receive either complete or timely vaccine courses. Therefore, it is important to investigate affordable and flexible ways to deliver this vaccine, which are safe and effective. A recent WHO-GAVI meeting to address impediments to the introduction of these vaccines in developing countries recognized the need to evaluate other regimens of Pnc conjugate vaccine as an important research priority. This study has been deliberately formulated with that need in mind. The site for this research is Fiji. Although health services are good, Pnc disease, particularly pneumonia, remains the commonest cause of childhood morbidity and mortality. Fiji has good vaccine coverage and was the first Pacific country to introduce Hib vaccine. The arrival of the new, expensive Pnc conjugate vaccine presents a dilemma for Fiji and many similar countries. The expense of this vaccine would consume a large portion of the health budget. This study has two components: 1. A Phase 2 immunogenicity study (involving 750 infants) to evaluate regimens using reduced numbers of doses of Pnc conjugate vaccine, and using timing of dosing and combinations with the Pnc polysaccharide (PS) vaccine that may be more suited to the epidemiology of Pnc disease in developing countries. 2. An epidemiological study will measure the burden of invasive Pnc disease and pneumonia in Fiji. This will be part of a global effort to address these issues, and will be used to develop rapid assessment tools for these diseases in developing countries. We will seek cofounding for this component.Read moreRead less