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
NMR Of Red Cells: Plasma Membrane Oxidoreductase, And Cation Transport
Funder
National Health and Medical Research Council
Funding Amount
$192,388.00
Summary
An interesting paradox exists with respect to the 'central' function of the red blood cell (RBC): it delivers the main oxidising capacity to the body (O2), but it also carries the chemically opposite functionality in its membrane, namely reducing capacity. The reduction of many oxidised proteins and metabolites in blood plasma is mediated by a plasma-membrane oxido-reductase (PMOR). Ascorbic acid (vitamin C) dramatically accelerates this rate of reduction but its precise molecular role is unknow ....An interesting paradox exists with respect to the 'central' function of the red blood cell (RBC): it delivers the main oxidising capacity to the body (O2), but it also carries the chemically opposite functionality in its membrane, namely reducing capacity. The reduction of many oxidised proteins and metabolites in blood plasma is mediated by a plasma-membrane oxido-reductase (PMOR). Ascorbic acid (vitamin C) dramatically accelerates this rate of reduction but its precise molecular role is unknown; neither is the immediate source of the reducing equivalents (electrons) known. Novel, non-invasive, 13C NMR methods have been developed, and others are planned in this project, to study the rate of reduction of Otest? compounds, including 13C-ferricyanide, and reactions of 13C-ascorbate. This will provide a quantitative understanding of the kinetics of the redox reactions in the intact cell. The transfer of negative charges (electrons) from the cell, in the longer term (minutes) inevitably must be matched by the movement of cations (positive charges). The main cation flux is mediated by Na+, K+-ATPase, but various cation exchange pathways are also involved in the total Oionic economy? of the cell. Of special interest will be the calcium-activated K+ (or Gardos) channel. This Oopens? inappropriately in malaria, sickle cell anaemia, and under blood bank storage conditions, and this is thought to be the basis of some of the pathological events in these conditions. The alkali-metal cation exchange pathway ( Na+-Li+) is more activate in the red cells of many patients with hypertension. So, multiple-quantum NMR methods will be used to monitor membrane transport and binding of cations to characterise the kinetics and regulation of the K+-channel, and the Na+-Li+ exchange reactions. The significance will lie in a basic understanding of, and possible 'diagnostic methods' for the biochemical processes that occur in red blood cells in health and disease.Read moreRead less