Clinical Immunology & Serology Chapter 1 PDF
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Uploaded by WellBalancedRadiance8883
Chattahoochee Technical College
Linda E. Miller and Christine Dorresteyn Stevens
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Summary
This document is an overview of clinical immunology, including introduction to immunity, and the immune system. It covers immunity and immunization, innate versus adaptive immunity, and cells of the innate and adaptive immune system. The document also provides a historical perspective on inducing immunity, including variolation and vaccination.
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6/26/2024 Chapter 1 Introduction to Immunity and the Immune System Preamble PowerPoints are a general overview and are provided to help students take notes over the video lecture ONLY. PowerPoints DO NOT cover the details needed for the Unit exam Each stud...
6/26/2024 Chapter 1 Introduction to Immunity and the Immune System Preamble PowerPoints are a general overview and are provided to help students take notes over the video lecture ONLY. PowerPoints DO NOT cover the details needed for the Unit exam Each student is responsible for READING the TEXTBOOK for details to answer the UNIT OBJECTIVES Unit Objectives are your study guide (not this PowerPoint) Test questions cover the details of UNIT OBJECTIVES found only in your Textbook! 1 6/26/2024 Chapter Overview Immunity and immunization Innate versus adaptive immunity Cells of the innate immune system Cells of the adaptive immune system Organs of the immune system Study of a host’s reactions to foreign substances Foreign substances that induce a host response Antigens Examples: pollen proteins, Immunology components of bacterial pathogens Condition of being resistant to Immunity infection Making a pathogen less virulent Attenuation Takes place through heat, aging, or chemical means 2 6/26/2024 Historical Attempts to Induce Immunity 1800s Dr. Louis Pasteur Developed several vaccines through attenuation: 1700s pathogens made less Dr. Edward Jenner virulent through heat, aging, Developed smallpox vaccine or chemical treatment from cowpox material Cross-Immunity – exposure 15th century Vaccination to one agent protects against another China and Turkey People inhaled powder from smallpox scabs to prevent smallpox Variolation Also known as natural immunity Ability to resist infection through normally present body functions Nonspecific: responses are the same Innate for all pathogens or foreign substances Immunity Prior exposure not required Effect is immediate Memory not generated 3 6/26/2024 Adaptive Immunity Characterized by specificity for each antigen (e.g., individual pathogens) Memory is generated The immune system “remembers” a prior exposure to an antigen and mounts an increased response upon repeated exposure Leukocytes (white blood cells or WBCs) Found in peripheral blood and lymphoid tissues Play key roles in innate and Cells of the adaptive immunity Immune Types Neutrophils, eosinophils, System and basophils Monocytes and macrophages Mast cells Dendritic cells Lymphocytes 4 6/26/2024 All WBCs Originate From Hematopoietic Stem Cells (HSC) in the Bone Marrow HSC gives rise to common myeloid precursors (CMP) and common lymphoid precursors (CLP). CMPs develop into WBCs that perform phagocytosis. CLPs develop into lymphocytes. Cells of the Innate Immune System Polymorphonuclear cells (PMNs) Neutrophils Eosinophils Basophils Monocytes/Macrophages Mast cells Dendritic cells 5 6/26/2024 Neutrophils Comprise 50% to 70% of WBCs in peripheral blood Primary function is phagocytosis Contain a multi-lobed and destruction of nucleus and neutral- foreign particles staining granules in cytoplasm Neutrophils First at the site of entry of infectious microorganism Diapedesis (move through blood vessel walls) to enter tissue Marginate, adhere, “walk through vessel wall” Chemotaxins (chemical messengers) “call” leukocytes to a particular site where they are needed Life span of 5 days after entering tissue 6 6/26/2024 Eosinophils Comprise 1% to 4% of WBCs in peripheral blood Functions: Phagocytosis Neutralization of products Contain a bi-lobed or released in allergic reactions ellipsoidal nucleus and Killing of parasites Release of cytokines red-orange cytoplasmic Granules contain enzymes and granules histaminase Basophils Comprise less than 1% of circulating WBCs Release histamine, ECFA, small amounts of heparin which induce and maintain allergic reactions Contain a bilobed Histamine is vasoactive nucleus and deep blue- Heparin is an anticoagulant purple cytoplasmic granules 7 6/26/2024 Monocytes and Macrophages Monocytes Macrophages In peripheral Originate from blood and is monocytes that the largest have migrated leukocyte to the tissues Large cells with a horseshoe-shaped nucleus, dull grayish Comprise 2% to blue cytoplasm, and 10% of fine granules circulating WBCs Monocytes Two types of granules One contains peroxidase, acid phosphotase and arylsulfatase – similar to neutrophils One contains beta-glucuronidase, lysozyme and lipase Digestive vacuoles may be seen Stay in blood for 70 hours then migrate to tissues 8 6/26/2024 Macrophages Adaptive immune Innate immune functions responses Phagocytosis and Process and present microbial killing antigens to T cells Anti-tumor cell activity Produce cytokines that Intracellular parasite regulate immune eradication responses Secretion of cell mediators Mast Cells Resemble basophils but larger and come from a different lineage Present in tissues (e.g., skin, connective tissue) Induce and maintain allergic reactions Plays a role in hypersensitivity Release of granules by mast cell destruction can cause anaphylactic shock. Can also function as APCs Can enhance and suppress the adaptive immune response. 9 6/26/2024 Dendritic Cells Have long membranous extensions that resemble nerve cell dendrites Roles in both innate and adaptive immunity Most potent phagocytic cell Most effective antigen-presenting cell (APC) Main function is to phagocytize antigen and present to helper T- Lymphocytes Cells of the Adaptive Immune System: Lymphocytes Represent Types between 20% B cells and 40% of T cells circulating Natural killer Small cells with a large, (NK) cells WBCs round nucleus, and sparse, light blue cytoplasm 10 6/26/2024 B Cells and Plasma Cells Major role in antibody production B-cell surface markers: Surface Ig, CD19, CD20, CD21, MHC Class II B cells mature in the bone marrow. B cells differentiate into plasma cells after contacting antigen. Plasma cells have oval or eccentric nuclei and secrete antibodies. Mature in the thymus; all are CD3+ T Cells Different subtypes perform unique functions. Helper T Cells Regulatory T Cells Cytotoxic T cells 11 6/26/2024 Helper T cells (Th; CD4+) produce cytokines that stimulate B cells in antibody production; assist other T cells in cell-mediated immunity. T Cells Regulatory T cells (Treg; CD4+) (continued) inhibit immune responses. Cytotoxic T cells (Tc; CD8+) destroy tumor cells and virus- infected cells. Innate Lymphoid Cells and Natural Killer Cells Innate lymphoid cells (ILC) have important roles in innate immunity and tissue remodeling. A major type of ILC is the natural killer (NK) cell: Large cells with kidney-shaped nuclei and granular cytoplasm Positive for CD16 and CD56 Kill virus-infected cells and tumor cells without needing prior exposure Destroy antibody-coated target cells 12 6/26/2024 Organs of the Immune System Primary lymphoid organs Bone marrow Large tissue that fills the core of all long flat bones Main source of hematopoietic stem cells, which develop into erythrocytes, granulocytes, monocytes, platelets, and lymphocytes Location for maturation of B lymphocytes Thymus Small, flat, bilobed organ found in the thorax Location for maturation of T lymphocytes Secondary lymphoid organs Receive mature lymphocytes Organs of from primary lymphoid organs Function as sites for contact the Immune with foreign antigens System Include: Spleen (continued) Lymph nodes Mucosal-associated lymphoid tissue (MALT) Cutaneous-associated lymphoid tissue (CALT) 13 6/26/2024 Spleen Largest 2° lymphoid organ Located in upper left quadrant of abdomen, just below diaphragm Red pulp Rich in macrophages Destroys old red blood cells (RBCs) Spleen (continued) White pulp ~20% of the total weight of the spleen Contains lymphoid tissue arranged around arterioles in a periarteriolar lymphoid sheath containing T cells Primary follicles Contain B cells attached to the sheath not yet stimulated by antigens. 14 6/26/2024 Lymph Nodes Located along lymphatic ducts, especially near joints and where arms and legs join the body Collect lymph fluid from adjacent tissues Lymphocytes and foreign antigens enter nodes via afferent lymphatic vessels. Secondary follicles Consist of antigen-stimulated proliferating B cells Location where transformation of B cells takes place Form plasma cells and memory cells when exposed to an antigen Lymph Nodes (continued) B lymphocytes are located in follicles within the cortex. Secondary follicles Consist of antigen-stimulated proliferating B cells Location where transformation of B cells takes place Form plasma cells and memory cells when exposed to an antigen T cells are mainly in the paracortex. 15 6/26/2024 MALT Found on mucosal surfaces of the gastrointestinal, respiratory, and urogenital tracts A main port of entry for foreign antigens MALT and Numerous macrophages and CALT lymphocytes present Examples: tonsils, appendix, Peyer’s patches CALT T cells, monocytes, macrophages, and dendritic cells found on skin Innate immunity is the ability of the body to resist infection through means of normally present, nonspecific body functions. Adaptive immunity is characterized by specificity, Summary memory, and dependence upon lymphocytes. All blood cells arise from hematopoietic stem cells in the bone marrow. 16 6/26/2024 The principal types of peripheral blood leukocytes are neutrophils, eosinophils, basophils, monocytes, and lymphocytes. Tissue cells involved in immunity Summary include mast cells, dendritic cells, and macrophages. (continued_1) Cells that are involved in the innate immune response and are actively phagocytic include neutrophils, monocytes, macrophages, and dendritic cells. Lymphocytes are the key cells involved in the adaptive immune response. B cells, a type of lymphocyte, develops in the bone marrow. Summary (continued_2) After contact with antigens, B cells differentiate into plasma cells that can secrete a specific antibody. T lymphocytes consist of three major subtypes: helper T cells (Th), cytotoxic T cells (Tc), and regulatory T cells (Treg). 17 6/26/2024 Natural killer (NK) cells kill virally infected or cancerous target cells without previous exposure to them. The bone marrow and the Summary thymus are considered primary lymphoid organs, where (continued_3) lymphocyte maturation occurs. Contact of lymphocytes with foreign antigen takes place in the secondary lymphoid organs such as the spleen, lymph nodes, MALT, and CALT. Postamble READ the TEXTBOOK for the details to answer the UNIT OBJECTIVES. USE THE UNIT OBJECTIVES AS A STUDY GUIDE All test questions come from detailed material found in the TEXTBOOK (Not this PowerPoint) and relate back to the Unit Objectives 18