Antigen Dose And TCR Repertoire In CD8+ T Cell Immunodominance Hierarchies
Funder
National Health and Medical Research Council
Funding Amount
$558,920.00
Summary
The CD8+, or killer , T lymphocytes (white blood cells) are the hit men of immunity, recirculating continually around the body to eliminate other cells that are dangerous because they are cancerous or infected with a virus. A major difficulty is that killer T cells also exert selective pressures that cause viruses and tumours to mutate and thus avoid immune control. This is a particularly serious problem for RNA viruses that readily mutate as they divide. These include the human immunodeficiency ....The CD8+, or killer , T lymphocytes (white blood cells) are the hit men of immunity, recirculating continually around the body to eliminate other cells that are dangerous because they are cancerous or infected with a virus. A major difficulty is that killer T cells also exert selective pressures that cause viruses and tumours to mutate and thus avoid immune control. This is a particularly serious problem for RNA viruses that readily mutate as they divide. These include the human immunodeficiency virus (HIV) that causes AIDS and, while the mutations that are most important with influenza viruses are those that modify viral surface proteins recognized by antibodies, such T cell escape mutants can also be a problem with influenza. The other reason why there is particular interest in promoting CD8+ T cell-mediated immunity to influenza is that the killer T cells are very cross-reactive. We have shown that vaccination approaches that prime mouse CD8+ T cells to resist influenza A viruses circulating currently in humans will also protect against the highly lethal, and dangerous H5N1 bird 'flu. The present flu vaccines only stimulate antibodies, so there is interest in the possibility of a major re-design. The CD8+ T cells recognize tiny elements (peptides) of the virus or tumour bound in the tip of our own transplantation, or class I major histocompatibility complex (MHCI) molecules. These pMHCI complexes are called epitopes. The focus here is on the use of novel genetic engineering strategies to find out how, when the virus mutates to disrupt the major epitopes seen by killer T cells, other minor epitopes can be abnormally emphasized in a way that promotes effective immune control. As we work on this with the relatively simple and safe influenza model we will concurrently develop strategies that may be of value in HIV and tumour immunity. Solving this problem could prove to be a substantial advance in the design of vaccines and immunotherapy approaches.Read moreRead less
Characterisation Of Cell-mediated Immune Responses In Burkholderia Pseudomallei Infection
Funder
National Health and Medical Research Council
Funding Amount
$239,250.00
Summary
The bacterium Burkholderia pseudomallei, causes a life threatening condition known as melioidosis. Melioidosis is emerging as an important infectious disease in tropical regions of Australia and South East Asia. Death rates following acute disease are extremely high. Despite the importance of B. pseudomallei in tropical public health, very little is known regarding how the body's defence mechanisms prevent the spread of infection. The wide distribution of melioidosis in tropical Australia and ot ....The bacterium Burkholderia pseudomallei, causes a life threatening condition known as melioidosis. Melioidosis is emerging as an important infectious disease in tropical regions of Australia and South East Asia. Death rates following acute disease are extremely high. Despite the importance of B. pseudomallei in tropical public health, very little is known regarding how the body's defence mechanisms prevent the spread of infection. The wide distribution of melioidosis in tropical Australia and other parts of the world, and the lack of basic scientific information regarding this disease, has prompted this study. The bacterium lives within the body's cells and therefore does not respond well to standard antibiotic treatment. Although some of the basic immune mechanisms have been identified, how protection to the organism develops remains unclear. In this project we will investigate the effect of B. pseudomallei on immune cells or lymphocytes. This study will determine the patients' immune responses to the bacteria causing the disease. Our research team has already successfully carried out work on several different aspects of melioidosis. The characterisation of the basic immune function determined in the proposed study will provide the scientific basis for improvement in treatment and the development of possible preventive strategies against melioidosis.Read moreRead less
Interplay Of Innate And Adaptive Immunity To Influenza A Virus
Funder
National Health and Medical Research Council
Funding Amount
$555,693.00
Summary
Influenza is an acute febrile respiratory illness caused by influenza virus infection, and may trigger potentially life-threatening complications especially in the young and elderly. Immunity against influenza virus involves integration of the innate and adaptive immune system. We will use cutting-edge 2-photon microscopy to determine the orchestration of innate and adaptive immune cell interactions during viral infection. Results may provide for enhanced therapeutic or protective measures.
Comparative Effectiveness Of Vaccine-induced SIV-specific CD8 T Cells
Funder
National Health and Medical Research Council
Funding Amount
$607,797.00
Summary
A HIV vaccine remains elusive. Although killer T cell immunity can provide partial protection from HIV disease, we don't know the best type of killer T cells to induce by vaccination. This project compares multiple HIV vaccine strategies in macaques. We will carefully study the quality of killer T cell immunity induced using novel and cutting-edge assays. We will identify the requirements for effective killer T cell immunity to HIV.
Effector And Memory CD8+ T Cell Responses To Engineered Influenza A Escape Mutants
Funder
National Health and Medical Research Council
Funding Amount
$465,210.00
Summary
T cells are a critical component of the immune system after infection with viruses. In particular, virus-specific CD8+ T cells can clear viral infections by killing virally-infected cells and the release of immunomodulators. These are called effector T cells. After the viral infection is cleared, a small proportion of T cells (around 5 to 10%) survives for many years and constitute a memory pool of virus-specific T cells. Memory T cells provide a rapid and effective protection in case of a repea ....T cells are a critical component of the immune system after infection with viruses. In particular, virus-specific CD8+ T cells can clear viral infections by killing virally-infected cells and the release of immunomodulators. These are called effector T cells. After the viral infection is cleared, a small proportion of T cells (around 5 to 10%) survives for many years and constitute a memory pool of virus-specific T cells. Memory T cells provide a rapid and effective protection in case of a repeated infection with the same virus, and hence result in a less severe disease. However, viruses often mutate their genes to escape such efficient T cell responses. In this study, we will investigate T cell responses after infection with mutated strains of influenza viruses. We will engineer a panel of mutant influenza viruses, which alter the nature and characteristics of T cells. We will analyse how efficient are these T cells and whether they can protect against a normal strain of influenza A. Subsequently, we will characterise quantitative and qualitative aspects of memory T cell pools after infection with mutant influenza viruses. Since a number of viruses such as influenza, HIV and HCV rapidly mutate their genes, our study will not only address the question of T cell responses to mutated influenza viruses, but also will provide an excellent model for investigating protective T cell responses to other viral infections.Read moreRead less
Evaluation Of Immune Correlates For Virus-specific CD8+ T Cells Following Prime-boost Vaccination
Funder
National Health and Medical Research Council
Funding Amount
$397,889.00
Summary
This project will use cutting-edge technology to evaluate the quality of virus-specific white blood cells generated following vaccination. Clinically relevant vaccination strategies will be analysed in a well characterised mouse model of infection to produce correlates associated with protective vaccine efficacy, particularly in an immunosupressed setting. This will lead to more focused research and ultimately the development of prophylactic and therapeutic HIV vaccines.
Defining The Role Of Lymphotoxin Alpha In Experimental Cerebral Malaria
Funder
National Health and Medical Research Council
Funding Amount
$158,250.00
Summary
Malaria kills millions of children every year. A major cause of death is cerebral malaria (CM) resulting from Plasmodium falciparum infection. At present, there is no effective vaccine available and drug-resistant parasites are widespread. CM is a serious neurological condition characterised by the sequestration of infected red blood cells (iRBC) in cerebral blood vessels. This event is thought to initiate a cascade of inflammatory reactions that ultimately lead to cerebral damage and often deat ....Malaria kills millions of children every year. A major cause of death is cerebral malaria (CM) resulting from Plasmodium falciparum infection. At present, there is no effective vaccine available and drug-resistant parasites are widespread. CM is a serious neurological condition characterised by the sequestration of infected red blood cells (iRBC) in cerebral blood vessels. This event is thought to initiate a cascade of inflammatory reactions that ultimately lead to cerebral damage and often death. The factors that cause the sequestration of iRBC in the brain are poorly understood. In this project, we will use an experimental model to define the changes that occur in the cerebral vessels during malaria. The identity of the cells and molecules that mediate the binding of iRBC to the blood vessels of the brain will be identified. It is anticipated that results from this work will increase our understanding of the development of pathology in the brain, as well as identify potential targets for modulation to prevent disease.Read moreRead less
Determining The Role Of Rel/NF-kB Transcription Factors In CD8 T Cell Homeostasis.
Funder
National Health and Medical Research Council
Funding Amount
$426,500.00
Summary
NF-kB proteins comprise a family of transcription factors that regulate key genes involved in immune responses, inflammation, cell death and proliferation. This family of proteins are potential drug targets for treatment of various diseases. How and when such inhibitors are used in clinical situations depends on understanding how and which cells of the immune system are specifically affected by the absence of NF-kB proteins. In a number of treatment settings intercurrent viral infections occur f ....NF-kB proteins comprise a family of transcription factors that regulate key genes involved in immune responses, inflammation, cell death and proliferation. This family of proteins are potential drug targets for treatment of various diseases. How and when such inhibitors are used in clinical situations depends on understanding how and which cells of the immune system are specifically affected by the absence of NF-kB proteins. In a number of treatment settings intercurrent viral infections occur frequently and therefore there is an even greater need to understand how the immune system may be affected or compromised in response to the primary treatment. This work will provide insights into the cellular and molecular mechanisms affected by the absnece of a particular NF-kB family member (NF-kB1) in CD8 T cells during normal T cell homeostasis and when challenged with viruses. What we learn from our experiments could have important implications for the development of vaccines.Read moreRead less
Discovery Of Long CD8+ T Cell Epitopes Uncovers A Hidden Reservoir Of Immunodominant, Anti-tumour Responses
Funder
National Health and Medical Research Council
Funding Amount
$480,127.00
Summary
Stimulating killer T cells to eliminate tumours has been one of the ultimate yet elusive goals of cancer vaccine development. Vaccines aimed at stimulating killer T cells are similar to those generated under natural conditions. However, special strategies are needed to vaccinate beneficial killer T cells that are not normally part of the natural immunity. In this project, we will explore such a scenario and dissect the related mechanisms contributing to such differential immune outcomes.
Characterisation Of An Antigen Presenting Cell Unique To Spleen
Funder
National Health and Medical Research Council
Funding Amount
$420,606.00
Summary
The body depends on a range of defence mechanisms to remove invaders that enter by various routes. Antigen presenting cells are central to immunity in that they engulf and destroy dead cells and pathogens and present pieces of those pathogens or 'antigens' to white blood cells called T and B lymphocytes. These cells then start to fight the infection or disease. A new type of antigen presenting cell will be investigated for its particular ability to arrest blood-borne pathogens and disease.