Cells of the immune system need to recognise characteristic viral and bacterial molecules, in order to identify infection. Some immune cells can detect the presence of viral and bacterial DNA. The cells respond by making a number of anti-viral or anti-bacterial molecules, as well as activating other cells to fight the infection. The effect of bacterial DNA can be mimicked by certain short synthetic pieces of DNA. The potent activity of this synthetic DNA (termed CpG DNA ) is being exploited in a ....Cells of the immune system need to recognise characteristic viral and bacterial molecules, in order to identify infection. Some immune cells can detect the presence of viral and bacterial DNA. The cells respond by making a number of anti-viral or anti-bacterial molecules, as well as activating other cells to fight the infection. The effect of bacterial DNA can be mimicked by certain short synthetic pieces of DNA. The potent activity of this synthetic DNA (termed CpG DNA ) is being exploited in a number of clinical trials for treatment of cancer and allergy, as well as to improve vaccinations. Despite the rapid advance towards clinical application, there is still much basic information to learn about how CpG DNA acts on cells. The molecule to which DNA binds in order to activate the cells is called TLR9. TLR9 is not on the surface of cells, but within cells. In a bacterial infection, cells called macrophages engulf and digest bacteria and release the bacterial DNA within the cell, where it binds to TLR9. In other cases, including when CpG DNA is used therapeutically, the DNA needs to be taken up into the cell. Evidence shows that there is a receptor on the cell surface which binds DNA, and takes it into the cell. In this project we propose to identify this DNA uptake receptor. Apart from the use of CpG DNA, there are a number of other proposals for the therapeutic use of DNA. Although it is known that DNA enters into cells, the route for this has not been established. Whilst CpG DNA can activate immune cells, some other distinct DNA molecules can prevent the activation. We will examine whether these inhibitory DNA molecules bind more effectively to TLR9 than the CpG DNA, but do not activate the cell. These inhibitory molecules are proposed as a therapy for the autoimmune disease lupus, which involves inappropriate responses to DNA, and is thought to involve TLR9. In order to develop therapies, a detailed knowledge of how they work is essential.Read moreRead less
I am a cellular immunologist interested in the study of cytokines and other regulatory molecules in inflammatory and immune responses. One key area relates to the effect on sunlight on cell-mediated immunity.
Recruitment And Activation Of Alternatively Activated Macrophages By Thioredoxin Peroxidases In Helminth Infections
Funder
National Health and Medical Research Council
Funding Amount
$243,000.00
Summary
This research will unlock the immunological steps that lead to the development of pathological consequences associated with infectious pathogens and human diseases. The investigation proposed is very timely, as there is a rapid growth in people acquiring infectious diseases in the developing world and inflammatory pathologies in the developed world such as artherosclerosis, asthma, and tumour progression. There is a common denominator between all of these diseases. The body loses its ability to ....This research will unlock the immunological steps that lead to the development of pathological consequences associated with infectious pathogens and human diseases. The investigation proposed is very timely, as there is a rapid growth in people acquiring infectious diseases in the developing world and inflammatory pathologies in the developed world such as artherosclerosis, asthma, and tumour progression. There is a common denominator between all of these diseases. The body loses its ability to regulate a particular type of immune response, termed Th2. This results in the production of a chronic inflammation, which causes lasting damage. We have previously pinpointed the activity of a particular type of white blood cell, the macrophage, as pivotal to the induction of the Th2 immune response. We have also identified a molecule, thioredoxin peroxidase (TPx) that triggers the macrophage to switch on Th2 responses. Once the TPx comes into contact with the surface of the macrophage cell, a series of proteins, called transcription factors become activated in a controlled cascade. This leads to the secretion of substances from the macrophage, which signal the development of Th2. We will identify the mechanism that TPx uses to initiate the process. We propose to investigate this sequence of events by using an in-vitro cell based model to study the enzymatic steps as the macrophage responds to TPx. This goal represents much more than scientific curiosity. A better understanding of the process may reveal how TPx switches on the macrophage. If the trigger for this could be found, it would present a new way to manipulate the macrophage. This will possibly unearth new drug targets and lead to more effective therapeutics against infectious diseases, asthma, artherosclerosis and cancer.Read moreRead less