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About this Chapter. Anatomy and function of immune system Response to different pathogens Innate immunity: nonspecific body defenses Acquired immunity: specific defenses that target one pathogen Combined defenses against bacteria and viruses Neuro-endocrine-immune interactions.
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About this Chapter • Anatomy and function of immune system • Response to different pathogens • Innate immunity: nonspecific body defenses • Acquired immunity: specific defenses that target one pathogen • Combined defenses against bacteria and viruses • Neuro-endocrine-immune interactions
Immune System: Functions • Protects from pathogens and foreign molecules • Parasites • Bacteria • Viruses • Removes dead or damaged cells • Attempts to recognize and remove abnormal cells
Immune System: Pathologies • Incorrect responses • Autoimmune disease (Type 1 diabetes) • Overactive responses • Allergies • Lack of response • Immunodeficiency disease (AIDS)
Viral Structure and Replication Figure 24-1a
Viral Structure and Replication Figure 24-1b
Body Defenses: Two Lines • Physical and chemical barriers • First line of defense • Skin, epithelial linings, and cilia • Acids, mucous, and lysozymes • Immune defenses • Second line of defense • Innate, non-specific, immediate response • Acquired; attack a specific pathogen (antigen)
Steps in an Immune Response • Detect and identify invader/foreign cells • Communicate, alarm, and recruit immune cells • Coordinate response among all participants • Suppress or destroy invader
Lymphatic System • Primary tissues • Bone marrow and thymus • Encapsulated tissues • Lymph nodes and spleen • Lymph vessels • Diffuse tissues
Lymphatic System: Anatomy Figure 24-2a
Lymphatic System: Anatomy Figure 24-2b
Key Cells of the Immune System • Leukocytes (white blood cells) • Eosinophils • Basophils and mast cells • Neutrophils • Monocytes and macrophages • Lymphocytes and plasma cells • Dendritic cells
Key Cells of the Immune System Figure 24-4
Immune Cell Groups • Morphological group • Granulocytes • Functional group • Phagocytes, cytotoxic cells, and antigen-presenting cells (APCs) • Mononuclear phagocyte system
Immune Cells: Function • Eosinophils • Allergic reactions • Parasitic diseases • Basophils • Release histamine • Inflammation
Immune Cells: Function • Neutrophils • Ingest bacteria • Release cytokines • Monocytes • Mature to macrophages • Phagocytic • APCs
Immune Cells: Function • Lymphocytes • Acquired immunity • Dendritic cells • Activate lymphocytes
Antigen-Presenting Cells Figure 24-5 (1 of 3)
Antigen-Presenting Cells Figure 24-5 (2 of 3)
Antigen-Presenting Cells Figure 24-5 (3 of 3)
Antigen-Presenting Cells Figure 24-5
Innate Immunity: Nonspecific • Physical and chemical barriers • Phagocytosis: macrophages, neutrophils, natural killer (NK) cells • Engulf and digest “tagged” cells • Inflammatory response
Innate Immunity: Phagocytosis Figure 24-6a
Innate Immunity: Phagocytosis Figure 24-6b
Phagosomes Lysosomal enzymes digest pathogens that have been enclosed in phagosomes Figure 24-7
NK cells • Eliminate virus-infected and tumor cells • Secrete interferons • Interferon-alpha and interferon-beta • Prevent viral replication • Interferon-gamma • Activates macrophages and other immune cells
Inflammatory Response: Roles • Attract immune cells and chemical mediators to site of infection • Produce physical barrier to prevent infection from spreading • Promote tissue repair
Inflammatory Response: Players • Histamines from mast cells • Swelling, edema, vasodilation • Interleukins • Fever, blood vessels more permeable to white blood cells and proteins, acute-phase proteins
Inflammatory Response: Players • Bradykinin • Pain and swelling • Complement cascade • Membrane attack complex
Inflammatory Response: Players Action of a membrane attack complex Figure 24-8
Acquired Immunity: Antigen-Specific • T lymphocytes • Helper T cells • Cytotoxic T cells • B lymphocytes • Plasma cells • Memory cells • NK cells
Acquired Immunity: Antigen-Specific • Naïve lymphocytes • Clonal expansion • Effector cells • Memory cells
Acquired Immunity: Antigen-Specific How clonal expansion leads to immunologic memory Figure 24-10 (1 of 4)
Acquired Immunity: Antigen-Specific Figure 24-10 (2 of 4)
Acquired Immunity: Antigen-Specific Figure 24-10 (3 of 4)
Acquired Immunity: Antigen-Specific Figure 24-10 (4 of 4)
B lymphocytes: Humoral Immunity • Immunoglobulins • Plasma and memory cells • Primary and secondary response
B lymphocytes: Humoral Immunity Memory in the immune system Figure 24-11
Plasma Cells: Antibodies • Five classes • IgG, IgA, IgE, IgM, IgD • Light and heavy chain • Fab region • Fc region
Plasma Cells: Antibody Structure Figure 24-12
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site Activates complement 6 5 Triggers mast cell degranulation Memory cells Plasma cells Antibody Secrete antibodies NK cell or eosinophil Bacterial toxins 2 Acts as opsonins 4 Activates antibody- dependent cellular activity Causes antigen clumping and inactivation of bacterial toxins 3 Enhanced phagocytosis Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site Memory cells Plasma cells Antibody Secrete antibodies Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13, step 1
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site Memory cells Plasma cells Antibody Secrete antibodies 2 Acts as opsonins phagocytosis Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13, steps 1–2
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site Memory cells Plasma cells Antibody Secrete antibodies Bacterial toxins 2 Acts as opsonins Causes antigen clumping and inactivation of bacterial toxins 3 Enhanced phagocytosis Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13, steps 1–3
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site Memory cells Plasma cells Antibody Secrete antibodies NK cell or eosinophil Bacterial toxins 2 Acts as opsonins 4 Activates antibody- dependent cellular activity Causes antigen clumping and inactivation of bacterial toxins 3 Enhanced phagocytosis Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13, steps 1–4
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site 5 Triggers mast cell degranulation Memory cells Plasma cells Antibody Secrete antibodies NK cell or eosinophil Bacterial toxins 2 Acts as opsonins 4 Activates antibody- dependent cellular activity Causes antigen clumping and inactivation of bacterial toxins 3 Enhanced phagocytosis Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13, steps 1–5
Functions of Antibodies 1 Activates B lymphocytes Antigen binds to antibody Antigen binding site Activates complement 6 5 Triggers mast cell degranulation Memory cells Plasma cells Antibody Secrete antibodies NK cell or eosinophil Bacterial toxins 2 Acts as opsonins 4 Activates antibody- dependent cellular activity Causes antigen clumping and inactivation of bacterial toxins 3 Enhanced phagocytosis Adapted from Jo Kuby, Immunology 2e (New York: W. H. Freeman, 1994) Figure 24-13, steps 1–6
T Lymphocytes: Cell-Mediated • T cell receptors • Cell activated by antigen • Major histocompatibility complex (MHC)