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Biology of Immune System

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Biology of Immune System Central University of South Bihar Panchanpur, Gaya, India E-Learning Resources Department of Biotechnology NB: These materials are taken/borrowed/modified/compiled from various resources like research articles and freely available internet websites, and are meant to be used solely for the teaching purpose in a public university, and for serving the needs of specified educational programmes. Dr. Jawaid Ahsan Assistant Professor Department of Biotechnology Central University of South Bihar (CUSB) Course Code: MSBTN2004C04 Course Name: Biology of Immune System Lymphoid System Anatomy of the Lymphoid System Lymphatic Capillaries Lymph Node Structure of Lymph Node Lymph Nodes • Functions include: • Filtration of particles and microorganisms to keep them out of general circulation. • Interaction of circulating antigens in lymph with lymphocytes to initiate immune response. • Activation, proliferation of B lymphocytes and antibody production. • Activation, proliferation of T lymphocytes. Bone marrow In birds, the bursa of Fabricius (Latin: Bursa cloacalis or Bursa fabricii) is the site of hematopoiesis. In birds B cells mature in the bursa of Fabricius. (The process of B-cell maturation was elucidated in birds—hence B for bursa.) In mammals the primary organ for B-lymphocyte development is the bone marrow, although the prenatal site of B-cell differentiation is the fetal liver. Unlike the thymus, the bone marrow does not atrophy at puberty, and therefore there is no concomitant decrease in the production of B lymphocytes with age. A diagram of the anatomy of a bone, showing the bone marrow in red Red marrow - mainly hematopoietic tissue; Red blood cells, platelets, and most white blood cells arise in red marrow. Yellow marrow - mainly made up of fat cells. At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type; only around half of adult bone marrow is red. Red marrow is found mainly in the flat bones, such as the pelvis, sternum, cranium, ribs, vertebrae and scapulae, and in the cancellous ("spongy") material at the epiphyseal ends of long bones such as the femur and humerus. Yellow marrow is found in the medullary cavity, the hollow interior of the middle portion of long bones. In cases of severe blood loss, the body can convert yellow marrow back to red marrow to increase blood cell production. Spleen • Largest accumulation of lymphoid tissue • Abundant phagocytic cells—defense against antigens in blood • Site of destruction of aged erythrocytes. • Production site of activated lymphocytes which are delivered to the blood. • THUS, an important blood filter and antibody- forming organ. The spleen is an organ found in virtually all vertebrate animals. Similar in structure to a large lymph node, the spleen acts primarily as a blood filter. As a part of the mononuclear phagocyte system, it metabolizes hemoglobin removed from senescent erythrocytes. The globin portion of hemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin, which is subsequently shuttled to the liver for removal. The spleen is brownish in color. It synthesizes antibodies in its white pulp and removes antibody-coated bacteria along with antibody-coated blood cells by way of blood and lymph node circulation. A study published in 2009 using mice showed it has been found to contain in its reserve half of the body's monocytes within the red pulp. These monocytes, upon moving to injured tissue (such as the heart), turn into dendritic cells and macrophages while promoting tissue healing. .
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  • Development of Hematopoietic, Endothelial, and Perivascular Cells from Human Embryonic and Fetal Stem Cells
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