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Immunology

Immunology. BIT 120 Chapters 11. Immunity. Ability of body to defend against infectious agents, foreign cells, abnormal cells Antigen: foreign substance/molecule which elicits an immune response  from virus, bacteria, mold, cancer, pollen

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Immunology

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  1. Immunology BIT 120 Chapters 11

  2. Immunity • Ability of body to defend against infectious agents, foreign cells, abnormal cells • Antigen: foreign substance/molecule which elicits an immune response •  from virus, bacteria, mold, cancer, pollen • Antibody protein found in blood attacks to one particular kind of antigen and counters its effect specifically binds to antigens and marks them for destruction

  3. Non-Specific Immunity:First Line of Defense • Does NOT distinguish between one invader and another • 1. Skin • 2. LYSOZYME in sweat, saliva, tears • enzyme which breaks bacterial cell wall • 3. mucous membranes line digestive and respiratory tract • 4. acid in stomach • 5. hair, cilia in respiratory tract

  4. Non-specific Immunity:Second Line of Defense • FIGURE 11.1 BLOOD CELLS • 1.Inflammatory reaction (Fig 11.5) • injury • injured cells release histamine • Dilation of capillaries (increases blood flow) • Increases permeability of caps • Allows: Macrophages move to tissue to eat invader • Effects: Redness, heat, swelling, pain • Anti-inflammatory drugs- aspirin, ibuprofen

  5. Non-specific Immunity:Second Line of Defense • 2.Interferon • released by virally infected cells • interferes with viral production of neighboring cells • 3. Phagocytes (engulf microorganisms) • A. Macrophages • B. Neutrophils • releases chemicals • 4. Natural killer cells • cause infected cells to lyse PERFORIN • cancer cells

  6. Macrophages

  7. Specific Immunity:Third Line of Defense • Comes into play when non-specific can’t do the job. • Specific for particular virus or bacteria • Explain about not getting same sickness twice. • 10E6 antigens in lifetime • KEY FEATURES • Lymphocytes (type of white blood cells) • B cells • T cells

  8. T L Y M P H O C Y T E

  9. Lymphocytes originatein Bone Marrow • B Lymphocytes T lymphocytes • circulate in blood and lymph circulate in blood an lymph • secretes antibodies attacks body’s cells that have been • infected with bacteria and virus • only responds to free antigen only responds to antigen on • body’s cells (needs APC) • defends against bacteria and virus also defends agst protozoans • fungi, cancer

  10. T cell Mediated Immunity Types of T Cells Helper Cytotoxic Memory • Microbe is ingested by macrophage • Foreign protein is displayed on surface • Helper T cells recognize foreign protein with their receptor 1. make more helper T cells • 2. stimulate growth of cytotoxic T cells (which lyse cells with perforin) • 3. activate B cells to make antibodies • Memory T cells

  11. Antibody-Mediated ImmunityHumoral Response • 1. B cell coated with its antibody (Immunoglobulin) • Antigen binds to Ab of one ‘clone’ • 2. CLONAL SELECTION • B cells becomes activated and divides/differentiates into • plasma cells which produce antibodies • Memory cells • Secondary immune response is stronger and longer • THIS SELECTION CAN ALSO BE STIMULATED BY HELPER T CELLS INTERACTING WITH B CELLS (Fig 11.9) • 3. Free Antibodies bind to antigen and cause phagocytosis and cell lysis

  12. Antibody Fig 42.6 FIG 42.11

  13. Macrophages and E. coli

  14. Allergies • Hypersensitivities to substances that are not harmful to body – • pollen • animal hair • Caused by IgE on mast cells • When antigen binds to antibody, • histamine is released from mast cell • Histamine causes cold-like symptoms • nasal irritation • tears • blood vessels dilate

  15. Anaphylactic Shock • Extremely sensitive to allergen • Mast cells release histamine • Blood vessels dilate • Precipitous drop in Blood Pressure (SHOCK) • Possibly fatal • Treatment • Epinephrine • Increases blood pressure

  16. Autoimmune Diseases • Body doesn’t distinguish between self and non-self correctly • lupus • insulin-dependent diabetes • rheumatoid arthritis • multiple sclerosis

  17. Immunodeficiency Diseases • SCID severe combined immunodeficiency • no B or T cells • TREATMENT Gene therapy • AIDS • Stress • Exams vs vacation research • decreased interferon levels and • decreased natural killer cells

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