INTRO-TO-IMMUNOSERO.pdf

IMMUNOSEROLOGY LECTURE/INTRO TO IMMUNOSERO 1. Origins of Immunology Immunology as a science began with the study of immunity, particularly through the 5. White Blood Cells Capable of Phagocytosis observation of how individuals who recovered Type of WBC...

IMMUNOSEROLOGY LECTURE/INTRO TO IMMUNOSERO 1. Origins of Immunology Immunology as a science began with the study of immunity, particularly through the 5. White Blood Cells Capable of Phagocytosis observation of how individuals who recovered Type of WBC Function from infectious diseases often did not contract Neutrophils Engulf and digest bacteria the same disease again. This phenomenon led and fungi. to early vaccination practices, such as Edward Macrophages Phagocytose pathogens and Jenner's smallpox vaccine in the late 18th dead cells; present antigens century, which laid the groundwork for modern to T cells. immunology. Dendritic Cells Capture and present antigens 2. Attenuated Vaccines to T cells; initiate adaptive An attenuated vaccine contains live pathogens immune response. that have been weakened or modified so they 6. Role of Tissue Cells in Immunity cannot cause disease in healthy individuals. Tissue cells, such as macrophages and dendritic These vaccines stimulate a strong immune cells, play a crucial role in immunity by acting as response by mimicking natural infection, leading antigen-presenting cells (APCs). They capture to long-lasting immunity. pathogens, process antigens, and present them to T 3. Humoral vs. Cellular Immunity Controversy cells, thereby initiating the adaptive immune The debate over humoral immunity (mediated response. Additionally, tissue cells release cytokines by antibodies produced by B cells) versus that modulate immune responses and inflammation. cellular immunity (mediated by T cells) was 7. Differences Between NK Cells and T Lymphocytes pivotal in advancing immunology. Early Natural Killer (NK) cells are part of the innate researchers, such as Emil von Behring and Paul immune system and can recognize and destroy virus- Ehrlich, focused on humoral immunity, while infected cells and tumors without prior sensitization. others, like Louis Pasteur, emphasized the role In contrast, T lymphocytes (T cells) are part of the of cellular immunity. This controversy spurred adaptive immune system and require specific further research, leading to a more antigen recognition to become activated and exert comprehensive understanding of the immune their effects. system. 8. Primary Lymphoid Organs 4. Innate vs. Adaptive Immunity Bone Marrow: Thymus: Innate Immunity: Adaptive Immunity: The site of The site where T cells mature The body's first line of A more specific and hematopoiesis; and differentiate, learning to defense, providing delayed response responsible for the distinguish between self and immediate but that develops over production of all non-self. nonspecific responses time. It involves the blood cells, including to pathogens. It activation of B cells. includes physical lymphocytes (B cells barriers (skin, mucous and T cells) and the membranes) and production of immune cells antibodies tailored to (neutrophils, specific pathogens. macrophages). SAPLAD, JOHNA MAY C. 1  IMMUNOSEROLOGY LECTURE/INTRO TO IMMUNOSERO 9. Secondary Lymphoid Organs - Lymph Nodes: Filter lymph and facilitate - Spleen: Filters blood, removes old red blood cells, and mounts interactions between lymphocytes and antigens. immune responses to blood-borne pathogens. - Mucosal-Associated Lymphoid Tissue (MALT): - Appendix: Contains lymphoid tissue that plays a role in gut Includes structures like the tonsils and Peyer's immunity. patches, providing immune surveillance at mucosal surfaces. 10. Lymph Node Function and Architecture Lymph nodes serve as filters for lymph fluid, trapping pathogens and foreign particles. They consist of an outer cortex (with follicles containing B cells) and an inner medulla (with T cells and macrophages). Lymph nodes facilitate the activation of lymphocytes and the generation of an immune response. 11. Primary vs. Secondary Follicles Primary Follicle: Contains naive B cells and has Secondary Follicle: Forms after an antigenic response, not yet encountered an antigen. containing germinal centers where B cells proliferate, differentiate, and undergo somatic hypermutation. 12. Cluster of Differentiation (CD) Clusters of differentiation (CD) are surface markers on immune cells used to identify and classify different cell types. Each CD marker corresponds to a specific function or stage of cell development, aiding in the study and understanding of immune responses. 13. Roles of T Cells and B Cells T Cells: B Cells: Primarily involved in cell-mediated immunity. Responsible for humoral immunity. They produce antibodies They recognize and destroy infected cells that bind to specific antigens, neutralizing pathogens and (cytotoxic T cells) or help activate other immune marking them for destruction by other immune cells. cells (helper T cells). DEFINITION OF TERMS IMMUNOLOGY Study of a host’s reactions when foreign substances are introduced into the body. Such foreign substances that induce a host response are called antigens ANTIGENS Foreign substances that induce a host response; all around us. ANTIBODY A glycoprotein produces by the body to neutralize and eliminate the antigen IMMUNITY The condition of being resistant to infection. ATTENUATION Means to make a pathogen less virulent; it takes place through heat, aging, or chemical means. INNATE (NI) Or natural immunity, is the individual’s ability to resist infection by means of normally present body functions. ADAPTIVE (AI) Type of resistance that is characterized by specificity for each individual pathogen, or microbial agent, and the ability to remember a prior exposure. SEROLOGY -The study of antigen-antibody reactions in vitro -The technological application of immunologic principles in the detection & monitoring of disease states. SAPLAD, JOHNA MAY C. 2  IMMUNOSEROLOGY LECTURE/INTRO TO IMMUNOSERO EARLY HISTORY OF IMUNOLOGY & SEROLOGY 1798 Edward Jenner discovered the immunity against smallpox 1883 Elie Metchnikoff discovered cellular immunity 1890s Emil Von Behring discovered humoral immunity 1896 Gruber and Durham described bacterial agglutination. Widal developed an agglutination test for typhoid fever. Kraus described precipitation. CELLS OF IMMUNE SYSTEM TYPES FEATURES FUNCTIONS Leukocytes found in peripheral blood play a role in both innate and adaptive immunity. (WBC) Neutrophils Approximately 50-70% of total First responder to infection, phagocytosis. peripheral WBC In the tissues they may wander randomly or be attracted Has a nucleus with 2-5 segments and to a specific area by chemotactic factors or chemo. cytoplasm filled with primary and secondary granules that contain enzymes and chemical Eosinophils 12 to 15 μm in diameter and normally Have an important role in neutralizing basophil and mast make up between 1% and 3% of the cell products. circulating WBCs in a nonallergic person Helminths coated with IgE are recognized by eosinophils via FceR and release major basic protein and eosinophil cationic protein. Basophils Basophils are the least common white Induce and maintain allergic reactions, stimulates blood cells, making up less than 1% of production of IgE. circulating WBCs, and are characterized by their small size (10-15 μm) and deep bluish-purple granules that often obscure the nucleus. Monocytes Largest cells in peripheral blood. 12- Phagocytosis, migrate to tissues to become macrophages. 22um in diameter. Location and Names: Has an irregularly folded or horseshoe- Lungs –alveolar cell shaped nucleus that occupies almost one- Liver –Kupffer cell half of the entire cells volume. Brain –microglial cell Cytoplasm stain dull-grayish blue and has Connective tissue -histiocyte a ground-glass appearance (fine dustlike Kidney –mesangial cell granule Lymphocytes Lymphocytes, comprising 20-40% of Subtypes are T cells, B cells, and NK cells. circulating white blood cells, are key T cell –produce cytokines. (cell mediated immunity) mediators of adaptive immunity found in B cells –produce antibody in adaptive immune response. blood and secondary lymphoid organs, and (Humoral immunity) can be identified by specific CD markers NK cells –involved in innate immunity. despite their similar appearance. SAPLAD, JOHNA MAY C. 3  IMMUNOSEROLOGY LECTURE/INTRO TO IMMUNOSERO TISSUE CELLS TISSUE CELLS LOCATION FUNCTIONS Macrophages lungs, liver, brain, bone, connective tissue, and other Microbial killing, intracellular parasite tissue. eradication, tumoricidal activity, phagocytosis, Play a role in initiating and regulating innate and and antigen presentation to T and B cell adaptive immune response Mast cells skin, connective tissue, mucosal epithelium, and found Longer life span than basophils especially around blood and lymphatic vessels. Granules contain acid phosphatase (ACP), alkaline phosphatase (ALP) and protease. Connective tissue cells that resemble basophils but Play a role in allergic reaction. are larger and have more granules Antigen presentation (APC) to T and B cells, Enhancement and suppression of the adaptive immune response. Induces hypersensitivity reaction Dendritic cell Skin –Langerhans cells Heart, lungs, liver, kidney and Most effective at antigen presentation, most GI tract –interstitial dendritic cells Secondary potent phagocytosis lymphoid organs and thymus –interdigitating dendritic cells Primary and secondary follicles of lymph nodes and spleen –follicular dendritic cells. Covered with long membranous extensions that make them resemble nerve cell dendrites. Are considered the most effective APC in the body and the most potent phagocytic cell. ORGANS OF THE IMMUNE SYSTEM A. PRIMARY LYMPHOID ORGANS BONE MARROW One of the largest tissues in the body Fills the core of all long flat bones Main source of hematopoietic stem cells, which develop into erythrocytes, granulocytes, monocytes, platelets, and lymphocytes. Maturation site for B cells where they randomly develop receptor sites that will recognize self and non-self. THYMUS Small, flat, bilobed organ found in the thorax Location for maturation of T lymphocytes. T cells in the thymus are called thymocytes. Functions of primary lymphoid organs Produces hematopoietic stem cells, maturation of B and NK cells, maturation of T cells. B. SECONDARY LYMPHOID ORGANS LYMPH NODES Small, encapsulated structure located along lymphatic ducts and serve as central collecting points for lymph fluid from adjacent tissues. They are especially numerous near joints. Filtration of antigen from the lymph fluid and generation of B cell SPLEEN Largest secondary organ Splenic tissue is divided into the red pulp and white pulp SAPLAD, JOHNA MAY C. 4  IMMUNOSEROLOGY LECTURE/INTRO TO IMMUNOSERO White pulp contains lymphoid tissue arranged around arterioles in a Periarteriolar Lymphoid Sheath (PALS) containing T cells. White pulp comprises about 20% of the total weight of the spleen. MUCOSA-ASSOCIATED Diffusely distributed lymphoid cells and follicles found in the gastrointestinal, respiratory, and LYMPHOID TISSUE urogenital tracts where lymphocytes and macrophages are localized in the main ports of entry for (MALT) foreign organisms. Cells found in lymph nodes and spleen are the same in MALT but the lymphoid cells in MALT are not encapsulated. Example: Payer’s patches in the lower ileum of the intestinal tract TONSILS Small masses of macrophages and lymphoid tissue found in the mucous membrane lining of the oral and pharyngeal cavities Responds to pathogens entering the respiratory and alimentary tracts CUTANEOUS- Epidermis has activated keratinocytes, specialized T cells, and Langerhans cells. ASSOCIATED LYMPHOID Dermis has helper and cytotoxic T cells, macrophages TISSUE (CALT) Filters blood Places where contact between T cells, antigen, and B cells occur. SUMMARY SAPLAD, JOHNA MAY C. 5