Blimp-1: A Master Regulator Of B-lymphocyte Terminal Differentiation?
Funder
National Health and Medical Research Council
Funding Amount
$154,250.00
Summary
B lymphocytes are the antibody-producing cells of the immune system. They are formed in the bone marrow, and are exported to the body to circulate, searching for signs of infection. These circulating cells are not fully mature, but when they encounter an invader, with the help of other immune cells, they change. Most become antibody-producing cells, the final, operational cells of the B cell lineage. A few cells are set aside as memory cells that can rapidly become antibody-producing cells shoul ....B lymphocytes are the antibody-producing cells of the immune system. They are formed in the bone marrow, and are exported to the body to circulate, searching for signs of infection. These circulating cells are not fully mature, but when they encounter an invader, with the help of other immune cells, they change. Most become antibody-producing cells, the final, operational cells of the B cell lineage. A few cells are set aside as memory cells that can rapidly become antibody-producing cells should the same infection occur again. This is the basis of vaccination. The secretion of antibodies into the serum (that can bind to and eliminate an invader anywhere in the body) is the main function of B lymphocytes. This project will study the genes that allow B cells to become antibody-secreting cells (called ASC). We will focus on the gene for Blimp-1, the B lymphocyte-induced maturation protein, which has been called the master regulator of ASC formation. This claim is based largely on circumstantial evidence, and has not been directly tested genetically. We have made a mouse in which the Blimp-1 gene has been altered so that we can disable it in carefully controlled way. Using this knockout mouse, we can directly test the requirement for Blimp-1 in ASC and in other cell types. We will study these animals, using many tests that can accurately measure the behaviour of isolated cells, or the immune responses of the animals. We will examine other genes that are thought to be required for ASC to form or to perform their work, to see if loss of Blimp-1 (a known gene silencer) has impacted on these other genes. In this way, we expect to identify the genetic program that drives a B cell to become a mature ASC. Using this knowledge, we hope eventually to be able to study diseases of ASC in humans (as occur in allergy, asthma, rheumatoid arthritis and leukaemia). This information may also be used to improve the outcome of vaccination.Read moreRead less
The Quantitative Regulation Of Antibody Forming Cell Differentiation
Funder
National Health and Medical Research Council
Funding Amount
$336,500.00
Summary
B lymphocytes are the antibody-producing cells of the immune system. After they are made in the bone marrow, they are exported to the body to circulate, searching for signs of infection. When they encounter an invader, they change, with the help of other immune cells, into antibody-producing cells. A small proportion of the cells are set aside as memory cells that can rapidly become antibody-producing cells should the same infection occur again in the future. This is the basis of vaccination. Th ....B lymphocytes are the antibody-producing cells of the immune system. After they are made in the bone marrow, they are exported to the body to circulate, searching for signs of infection. When they encounter an invader, they change, with the help of other immune cells, into antibody-producing cells. A small proportion of the cells are set aside as memory cells that can rapidly become antibody-producing cells should the same infection occur again in the future. This is the basis of vaccination. The secretion into serum of antibodies that can bind to and eliminate an invader anywhere in the body is the main function of B lymphocytes. This project studies how a B cell changes into an antibody-producing cell. We will learn very basic and detailed quantitative aspects of the process, such as: -How long does it take to become an antibody-producer once a B cell detects an invader? -Do they-must they divide while they are changing? -How do hormones from other cells regulate the process? Do they increase division, survival, change the properties of the B cells, or improve their output? We will study all these responses in detail, so that we can make a model that can accurately predict the outcome of a particular set of circumstances. We will study the genes that are known to be required for antibody-producing cells to form, or to do their work. We will also study animals whose immune systems are under- or over-active, to find out what part of the antibody-producing process is faulty. We may be able to predict where the problem lies, by comparing these animals cells to our model, and therefore to suggest a remedy. Using this information, we hope eventually to be able to study diseases of antibody producing cells in humans (as occur in allergy, asthma, rheumatoid arthritis and leukaemia), to be able to identify the precise cause of the problem, and to suggest a therapy. This information may also be used to improve the outcome of vaccination.Read moreRead less
Viral disease is a major health hazard in the modern world. SV40 is a relatively simple virus which must enter mammalian cells in order to replicate. As it does so, it causes the infected cell to divide and hence triggers tumour formation in the host. This proposal is aimed at understanding how SV40 enters cells, and then passes to the nucleus where it replicates. Most viruses have hijacked existing pathways into cells. For example, some viruses have used the pathway by which cells take up nutri ....Viral disease is a major health hazard in the modern world. SV40 is a relatively simple virus which must enter mammalian cells in order to replicate. As it does so, it causes the infected cell to divide and hence triggers tumour formation in the host. This proposal is aimed at understanding how SV40 enters cells, and then passes to the nucleus where it replicates. Most viruses have hijacked existing pathways into cells. For example, some viruses have used the pathway by which cells take up nutrients from the external medium. However, we have shown that SV40 uses a completely novel pathway involving surface pits called caveolae. The subsequent steps in the pathway are unknown and have been difficult to study. We have discovered a number of agents which inhibit infection by SV40. In this proposal we will characterise the infectious entry pathway by investigating exactly where in the cell these agents work. We will then isolate the virus from within the cell and attempt to reconstitute part of the viral entry pathway in vitro. These studies will provide insights into the entry pathway of the virus which may lead to new therapeutic strategies to combat viral disease. In addition, study of this pathway, leading from the cell surface to the nucleus, may provide new avenues for drug delivery and-or gene targetting.Read moreRead less
Tumour cells are often characterized by defects in signaling pathways. One of the most important signaling cascades involved in the development of cancer is the EGFR-Ras-MAPK pathway. EGFR is often overexpressed in breast cancer, leading to enhanced Ras signaling (hyperactive Ras) and cell transformation. The proposed project aims to identify the molecular mechanisms that can downregulate hyperactive Ras and will make a valuable contribution to our understanding of EGFR-Ras related cancers.