Elucidating Mechanisms For The Biological Activities Of CD46.
Funder
National Health and Medical Research Council
Funding Amount
$228,000.00
Summary
The CD46 protein enables entry into cells of a number of different pathogens, including the measles virus, Neisseria meningitidis (the major cause of meningococcal disease), Neisseria gonorrhoea, Human Herpes Virus 6, and group A streptococcus. In addition, by binding to a key blood component that is often attached to foreign pathogens, CD46 can facilitate binding and entry of other pathogens. As well as facilitating entry of the pathogen, it has recently become apparent that CD46 binding trigge ....The CD46 protein enables entry into cells of a number of different pathogens, including the measles virus, Neisseria meningitidis (the major cause of meningococcal disease), Neisseria gonorrhoea, Human Herpes Virus 6, and group A streptococcus. In addition, by binding to a key blood component that is often attached to foreign pathogens, CD46 can facilitate binding and entry of other pathogens. As well as facilitating entry of the pathogen, it has recently become apparent that CD46 binding triggers a wide range of responses from the human host. Some of these responses are likely to further facilitate survival and proliferation of the pathogen, but others are more likely to facilitate host defence. For examples, signals triggered by binding to CD46 can both abrogate some aspects of the immune response (and it is though that this immunosuppression contributes to the secondary infections that cause the death of nearly one million children each year) and facilitate other aspects of the immune response. By understanding the mechanisms by which CD46 triggers these complex responses, we firstly be able to dissect how important each of these processes are to the overall pathogenecity of the virus or bacteria. Furthmore, this understanding will allow us to design better vaccines and drugs to combat these diseases.Read moreRead less
The C-type Lectin, Mincle, Is A Macrophage Receptor For Candida Albicans.
Funder
National Health and Medical Research Council
Funding Amount
$465,210.00
Summary
The yeast Candida albicans is an important opportunistic infection that causes both mucosal and disseminated disease in patients whose innate or adaptive immune responses are impaired Infection and proliferation results in fungal colonisation of the tissues, and a variable degree of tissue damage. The latter is determined both by the virulence properties of the organism and by the genetic makeup of the host. This large, extracellular pathogen is eradicated from the body predominantly by acavenge ....The yeast Candida albicans is an important opportunistic infection that causes both mucosal and disseminated disease in patients whose innate or adaptive immune responses are impaired Infection and proliferation results in fungal colonisation of the tissues, and a variable degree of tissue damage. The latter is determined both by the virulence properties of the organism and by the genetic makeup of the host. This large, extracellular pathogen is eradicated from the body predominantly by acavenger (phagocytic) cells, which are also important in determining the severity of the associated tissue lesions. A phagocytic cell that is central to both innate and adaptive immune responses is the macrophage, which not only takes up and kills the yeast, but also is capable of of killing and digesting it, and presenting the components to cells of the adaptive immune system. This project is based on the postulate that the outcome and severity of infection is determined, at least in part, by the early functional response of the macrophage to the overall virulence properties of the yeast. The response is initiated by interactions with cell-surface receptors, and this study will show that a novel macrophage receptor, Mincle, is an important part of the innate immune response to fungal infections. We have shown that it is associated with differences in susceptibility to yeast infections in inbred mouse strains; it can discriminate between different isolates of the yeast; and it initiates the inflammatory signalling cascade. Our project will define the specific role of this receptor in fungal infection. The results will be important in understanding the basic biology of host resistance, and will offer new opportunities for therapeutic intervention by selectively blocking or modifying different activation pathways.Read moreRead less