Schistosomes are parasitic flukes that survive in the blood vessels of their human hosts for many years. More than 200 million people are infected in developing countries, and Australian travelers to these regions are often infected. As larval schistosomes mature, they undergo physiological changes in the their outer surface, the tegument, and rapidly become refractory to vigorous immune responses. In the 1960's, researchers proposed that schistosomes evade otherwise destructive immune responses ....Schistosomes are parasitic flukes that survive in the blood vessels of their human hosts for many years. More than 200 million people are infected in developing countries, and Australian travelers to these regions are often infected. As larval schistosomes mature, they undergo physiological changes in the their outer surface, the tegument, and rapidly become refractory to vigorous immune responses. In the 1960's, researchers proposed that schistosomes evade otherwise destructive immune responses by masking their presence through the adsorption of host molecules onto the parasite surface. Intriguingly, most of the molecules adsorbed by the parasite are proteins involved in immune responses, such as MHC and immunoglobulins. In order to understand the molecular basis of schistosome maturation and masking, we recently isolated a protein that binds host IgG-Fc from the surfaces of schistosomes. We hypothesise that masking proteins expressed on the surface of developing parasites interfere with the development of protective immune responses by masking the otherwise susceptible tegument. Moreover, masking proteins are ideal candidate antigens for anti-schistosome vaccines. We now propose to test this hypothesis by identifying schistosome surface proteins that acquire host immune molecules, and isolate the genes encoding these parasite masking proteins. Masking proteins will be identified using protein-based affinity methods and differentially expressed gene- and protein-based methods. Recombinant masking proteins will then be assessed as unmasking vaccines in a mouse model of schistosomiasis. Elucidation of these aims should help to unravel the widely reported enigma of schistosome masking and the long-term survival of the parasite in the human bloodstream. By unmasking these parasites from their host-derived cloak, novel methods of controlling schistosomiasis will be revealed and efforts to develop a vaccine will be greatly accelerated.Read moreRead less
The Role Of Aire In Immunological Tolerance And Autoimmunity
Funder
National Health and Medical Research Council
Funding Amount
$434,134.00
Summary
The immune system is designed to protect us from foreign pathogens such as bacteria, viruses and parasites. This is achieved through lymphocytes which recognise foreign pathogens. However in 5-6% of the population the immune system attacks the host and induces autoimmunity. We aim to understand the mechanisms which control the production of self-reacting lymphocytes and how we may reduce the incidence of autoimmunity.
Inflammatory diseases, such as autoimmune diseases, result from an overactive immune system. A new therapy that is currently under trial is the use of special blood cells, called Treg cells, whose function is to suppress unwanted immune responses. This application evaluates the efficacy and safety of such treatments.
Tolerogenic Dendritic Cells In Common Marmoset Renal Transplantation
Funder
National Health and Medical Research Council
Funding Amount
$162,756.00
Summary
ORGAN TRANSPLANT PATIENTS currently need life-long immune suppressing drugs to prevent rejection, often using 15 medications a day, costing Australia $52M in 2002. These drugs increase risks of infection and cancer. 90% of patients develop some form of cancer over 30 years. They also cause non-specific side effects including high blood pressure, diabetes and osteoporosis. The average lifespan of a kidney transplant is 8-15 years. Major causes of kidney transplant loss are rejection and drug toxi ....ORGAN TRANSPLANT PATIENTS currently need life-long immune suppressing drugs to prevent rejection, often using 15 medications a day, costing Australia $52M in 2002. These drugs increase risks of infection and cancer. 90% of patients develop some form of cancer over 30 years. They also cause non-specific side effects including high blood pressure, diabetes and osteoporosis. The average lifespan of a kidney transplant is 8-15 years. Major causes of kidney transplant loss are rejection and drug toxicity. TRANSPLANTS ARE REJECTED when a recipient's immune system sees the kidney as foreign. Immune suppressing drugs prevent rejection by stopping the reaction to foreign tissues, but this causes increased infection and cancer risk. IMMUNE TOLERANCE means the recipient's immune system sees a transplant not as foreign but as part of itself, no longer reacting to it. If tolerance could be achieved for transplants, patients wouldn't need to use immune suppressing drugs. Costs of immune suppression would be nil. Tolerance is the best long-term solution for patients needing transplants. Tolerance has been achieved in various ways in mice models. DENDRITIC CELLS can be used to induce tolerance as they can silence a recipient's immune system, preventing it from seeing transplant tissues as foreign. We have shown in mice that a single infusion of a certain type of dendritic cells caused prolonged transplant tolerance without needing immune suppression. This project aims to use dendritic cells to induce tolerance in a marmoset model - a required step before allowing this therapy to be done in humans. PRIMATES like MARMOSETS have close genetic identity to humans and are ideal transplant models as their immune systems react much more like humans than other animals. Marmosets are not an endangered species and are smaller, cheaper and easier to care for than other primates. Ultimately, experiments in other species would need repeating in primates before human trials could be done.Read moreRead less
The Role Of Dendritic Cell Subsets In The Decision Between T Cell Tolerance And Immunity
Funder
National Health and Medical Research Council
Funding Amount
$445,009.00
Summary
The immune system protects the body against infection by means of a population of circulating white blood cells called lymphocytes. Each lymphocyte has on its surface its own particular receptor which recognises only one out of the universe of possible substances. Receptors are generated in a semi-random way, using a combination of elements encoded by the genes, and it is possible to generate receptors that react with the body itself, rather than with invading organisms. If the cells bearing the ....The immune system protects the body against infection by means of a population of circulating white blood cells called lymphocytes. Each lymphocyte has on its surface its own particular receptor which recognises only one out of the universe of possible substances. Receptors are generated in a semi-random way, using a combination of elements encoded by the genes, and it is possible to generate receptors that react with the body itself, rather than with invading organisms. If the cells bearing these self-reactive receptors become activated, an autoimmune disease ensues. The question of how lymphocytes can tell the difference between the body itself and foreign organisms is of major interest to immunologists. One of the first ideas was that self-reactive lymphocytes are inactivated by making reactions early in life. Despite the simplicity and intellectual appeal of this idea, it is inconsistent with a large body of experimental evidence. On the basis of number of new experiments, I have proposed an alternative model of self tolerance for one of the subsets of lymphocytes. In this model, the cells that help lymphocytes to recognise particular substances possess the property of distinguishing self from foreign, and pass that information on. The aim of this project is to provide direct experimental evidence in support of the model. Many of our attempts to deal with medical problems related to the immune system have been hampered by our lack of understanding of exactly how immune tolerance is controlled. If my model proves to be correct, it will be possible to manipulate immune responses with far greater effectiveness, providing new treatments for autoimmune disease, allergy, graft rejection and vaccination.Read moreRead less
Tolerogenic Dendritic Cells In Kidney Transplantation: Studies In Common Marmoset Monkeys
Funder
National Health and Medical Research Council
Funding Amount
$124,014.00
Summary
Kidney transplantation is the preferred treatment for end-stage kidney disease, but requires immunosuppressive drugs to prevent transplant rejection. However, long-term immunosuppression can have toxic side effects and increase the risks of infection and cancer. This research examines the therapeutic potential of dendritic cells (a specialised immune cell-type) to promote tolerance of the transplant kidney, while enabling maintenance of normal immune function and avoidance of immunosuppression.
Immunological Changes During Pregnancy And The Impact On Viral Hepatitis Infection
Funder
National Health and Medical Research Council
Funding Amount
$353,355.00
Summary
Hepatitis B virus (HBV) can cause long term health problems particularly affecting the liver and can be passed from mother to baby. Despite the availability of a HBV vaccine babies can still become infected. During pregnancy there are changes in a woman’s immune system which may impact on HBV infection and make transmission to the baby more likely. This research aims to explore the changes in a woman’s immune system and the impact this has on risks for hepatitis and transmission to the baby.