Description
This comprehensive tertiary-level lecture by Dr S. M. Munsaka provides a foundational introduction to immunology, focusing on the cells, tissues, and organs of the immune system. Designed for students pursuing degrees, diplomas, or certificates in biomedical sciences, medicine, or related health programmes at the University of Zambia and other institutions, the material covers the historical perspective of immunology and the three lines of host defense. It details the structure and function of innate immune cells, including phagocytes and natural killer cells, and adaptive immune cells, specifically B lymphocytes and T lymphocytes. The notes explain the development, maturation sites, and effector functions of these cells, alongside a clear comparison of humoral and cell-mediated immunity. The roles of primary lymphoid organs like the bone marrow and thymus, and secondary lymphoid organs including lymph nodes, spleen, and mucosal-associated lymphoid tissues are thoroughly described. Additionally, the lecture introduces key concepts in infectious disease, host-microbe interactions, and the importance of the normal flora. This resource is an excellent study guide for university students preparing for exams, offering a systematic overview of immunological principles essential for understanding health and disease. Access these notes to strengthen your foundational knowledge for tertiary immunology courses and examination success.
What's inside
Introduction to the Immune System (Cells and Tissues) S. M. Munsaka, BSc., MSc., PhD Department of Biomedical Sciences School of Health Sciences The University of Zambia Lecture Structure/Objectives Cells and tissues of the immune system Lymphocytes, antigen presenting cells and granulocytes Primary and secondary lymphoid organs Bone marrow, thymus, spleen, lymph nodes, mucosal associated lymphoid tissues and cutaneous associated lymphoid tissues Basic development morphology and function of the immune system and immune cells Introduction to infectious disease Historical perspective From birth we are exposed to microorganisms that can potentially cause disease, also cancers 430BC: Historian Thucydides in Athens recorded that only those who recovered from plague could nurse the sick and not contract the disease (immunis- ‘exempt’) Fifteenth century: Chinese and Turks performed variolation Dried smallpox pustules were inhaled or inserted in the skin 1798: Edward Jenner improved variolation Injected fluid from cowpox patient into healthy individuals 1881: Louis Pasteur describes attenuation of B anthracis 1885: Louis Pasteur administered Rabbis vaccine (first vaccine) Structure of the Immune System First line: Anatomical /Mechanical barriers (Skin and mucous membranes) Chemical barriers (acid and antibacterial peptides) Complement proteins, lysozyme and defensins Physiological barriers (temperature, pH) Second line: innate immune cells Phagocytes (monocytes/macrophages, neutrophils and dendritic cells) Natural killer cells (NKCs) Inflammatory cells (mast cells, basophils, eosinophils) Third line: adaptive immune cells Lymphocytes (T cells and B cells) Humoral immunity: Immunoglobulins (antibodies) Cell-medicated immunity: T cells Effector and memory responses Comparison Between Innate and Acquired Immunity Innate Immunity: 1st and 2nd line of defense Immediate response with no improvement with repeated exposure React against microbes but not against noninfectious substances or host tissue Adaptive or acquired immunity (3rd line of defense) Specificity: ability to recognize different microbes (self/non- self recognition) Flexibility (adaptability): ability to recognize newly evolved microbes (diversity) Memory: ability to remember previous responses and to react more quickly and more intensely •Humoral immunity: Antibodies in circulation eliminate infectious agent •Mechanisms •Neutralization/blocking •Antibody dependent-cell mediated cytotoxicity (ADCC) •Opsonization •Complement fixation •Cell-mediated immunity:T cells activate macrophage to kill phagocytosed microbe or kill infected cells Two Types of Acquired Immune Responses Development of Cells of the immune system Cells of the immune system Lymphocytes B and T cells (Th/CD4 and Tc/CD8 cells) Natural killer cells (NK cells) Antigen presenting cells B cells, monocytes/macrophages, dendritic cells Cells that produce inflammatory mediators (granulocytes) Neutrophils, basophils, eosinophils, mast cells Important in helminth and protozoan infections Involved in allergy B Cells Mature within the borne marrow Mature in the bursa of fabricus in birds Express B cell receptor (immunoglobulin/antibody molecules) on the surface Upon encounter with antigen, B cells differentiate into effector B cells (plasma cells) that secrete antibodies and memory B cells.
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