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Innate Immunity06


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Innate Immunity06

  1. 1. Eugene P. Mayer Office: Bldg. #2, Rm. B18 Phone: 733-3281 Email: MAYER@MED.SC.EDU
  2. 2. Innate (Nonspecific) Immunity
  3. 3. Overview of the Immune System Interactions between the two systems Immune System Innate (Nonspecific) 1 o line of defense Adaptive (Specific) 2 o line of defense Protects/re-exposure Cellular Components Humoral Components Cellular Components Humoral Components
  4. 4. Comparison of Innate and Adaptive Immunity <ul><li>No memory </li></ul><ul><li>No time lag </li></ul><ul><li>Not antigen specific </li></ul><ul><li>A lag period </li></ul><ul><li>Antigen specific </li></ul><ul><li>Development </li></ul><ul><ul><li>of memory </li></ul></ul>Innate Immunity Adaptive Immunity
  5. 5. Cells of the Immune System Immune System Myeloid Cells Lymphoid Cells Granulocytic Monocytic T cells B cells Neutrophils Basophils Eosinophils Macrophages Kupffer cells Dendritic cells Helper cells Suppressor cells Cytotoxic cells Plasma cells NK cells
  6. 6. Development of the Immune System ery pl mye neu m φ lym nk thy CD8 + CD4 + CTL TH2 TH1
  7. 7. Function of the Immune System (Self/Non-self Discrimination) <ul><li>To protect from pathogens </li></ul><ul><ul><li>Intracellular ( e.g. viruses and some bacteria and parasites) </li></ul></ul><ul><ul><li>Extracellular ( e.g. most bacteria, fungi and parasites) </li></ul></ul><ul><li>To eliminate modified or altered self </li></ul>
  8. 8. Infection and Immunity Balance infection immunity Bolus of infection x virulence immunity Disease =
  9. 9. Effects of the Immune System <ul><ul><ul><li>Beneficial: </li></ul></ul></ul><ul><ul><ul><ul><li>Protection from Invaders </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Elimination of Altered Self </li></ul></ul></ul></ul><ul><ul><ul><li>Detrimental: </li></ul></ul></ul><ul><ul><ul><ul><li>Discomfort and collateral damage (inflammation) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Damage to self (hypersensitivity or autoimmunity) </li></ul></ul></ul></ul>
  10. 10. Overview of the Immune System Immune System Innate (Nonspecific) Adaptive (Specific) Cellular Components Humoral Components Cellular Components Humoral Components
  11. 11. Innate Host Defenses Against Infection <ul><li>Anatomical barriers </li></ul><ul><ul><li>Mechanical factors </li></ul></ul><ul><ul><li>Chemical factors </li></ul></ul><ul><ul><li>Biological factors </li></ul></ul><ul><li>Humoral components </li></ul><ul><ul><li>Complement </li></ul></ul><ul><ul><li>Coagulation system </li></ul></ul><ul><ul><li>Cytokines </li></ul></ul><ul><li>Cellular components </li></ul><ul><ul><li>Neutrophils </li></ul></ul><ul><ul><li>Monocytes and macrophages </li></ul></ul><ul><ul><li>NK cells </li></ul></ul><ul><ul><li>Eosinophils </li></ul></ul>
  12. 12. Anatomical Barriers - Mechanical Factors Flushing action of tears, saliva, mucus, urine Epithelium ( e.g. nasopharynx) Mucociliary elevator Ciliated epithelium ( e.g. respiratory tract) Peristalsis Non-ciliated epithelium ( e.g. GI tract) Mucous Membranes Physical barrier Desquamation Squamous epithelium Skin Mechanism Cell type System or Organ
  13. 13. Anatomical Barriers - Chemical Factors Opsonin Sufactants (lung) Antimicrobial Defensins (respiratory & GI tract) Low pH Lysozyme and phospholipase A HCl (parietal cells) Tears and saliva Mucous Membranes Anti-microbial fatty acids Sweat Skin Mechanism Component System or Organ
  14. 14. Anatomical Barriers - Biological Factors Antimicrobial substances Competition for nutrients and colonization Normal flora Skin and mucous membranes Mechanism Component System or Organ
  15. 15. Humoral Components Compete with bacteria for iron Lactoferrin and transferrin Increase vascular permeability Recruitment of phagocytic cells Β -lysin from platelets – a cationic detergent Coagulation system Lysis of bacteria and some viruses Opsonin Increase in vascular permeability Recruitment and activation of phagocytic cells Complement Various effects Cytokines Breaks down bacterial cell walls Lysozyme Mechanism Component
  16. 16. Cellular Components Killing of virus-infected and altered self targets NK and LAK cells Killing of certain parasites Eosinophils Phagocytosis and intracellular killing Extracellular killing of infected or altered self targets Tissue repair Antigen presentation for specific immune response Macrophages Phagocytosis and intracellular killing Inflammation and tissue damage Neutrophils Functions Cell
  17. 17. Phagocytosis and Intracellular Killing
  18. 18. Phagocytes - Neutrophils (PNMs) <ul><li>Characteristic nucleus, cytoplasm </li></ul><ul><li>Granules </li></ul><ul><li>CD 66 membrane marker </li></ul>
  19. 19. Characteristics of Neutrophil Granules primary granules contain cationic proteins, lysozyme, defensins, elastase and myeloperoxidase secondary granules contain lysozyme, NADPH oxidase components, lactoferrin and B12-binding protein azurophilic; characteristic of young neutrophils; specific for mature neutrophils
  20. 20. <ul><li>Characteristic nucleus </li></ul><ul><li>Lysosomes </li></ul><ul><li>CD14 membrane marker </li></ul>Phagocytes - Macrophages
  21. 21. Phagocyte Response to Infection <ul><li>The SOS Signals </li></ul><ul><ul><li>N-formyl methionine-containing peptides </li></ul></ul><ul><ul><li>Clotting system peptides </li></ul></ul><ul><ul><li>Complement products </li></ul></ul><ul><ul><li>Cytokines released by tissue macrophages </li></ul></ul><ul><li>Phagocyte response </li></ul><ul><ul><li>Vascular adherence </li></ul></ul><ul><ul><li>Diapedesis </li></ul></ul><ul><ul><li>Chemotaxis </li></ul></ul><ul><ul><li>Activation </li></ul></ul><ul><ul><li>Phagocytosis and killing </li></ul></ul>
  22. 22. Attachment via Receptors: IgG FcR ScavengerR Complement R Toll-like R Initiation of Phagocytosis
  23. 23. Phagocytosis <ul><li>Attachment </li></ul><ul><li>Pseudopod extension </li></ul><ul><li>Phagosome formation </li></ul><ul><li>Granule fusion </li></ul><ul><li>Phagolysosome formation </li></ul>
  24. 24. Respiratory Burst Oxygen-Dependent Myeloperoxidase-Independent Reactions Toxic compounds – Superoxide anion (O 2 - ), Hydrogen peroxide (H 2 O 2 ), Singlet oxygen ( 1 O 2 ) and Hydroxyl radical (OH*) Pentose-P + NADPH G-6-P-dehydrogenase Glucose +NADP + NADPH oxidase Cytochrome b558 NADP + + O 2 - NADPH + O 2 Superoxide dismutase H 2 O 2 + 1 O 2 2O 2 - + 2H + 2O 2 - + H 2 O 2 OH* + OH - + 1 O 2
  25. 25. Respiratory Burst Oxygen-Dependent Myeloperoxidase-Dependent Reactions myeloperoxidase OCl - + H 2 O H 2 O 2 + Cl - 2OCl - + H 2 O 1 O 2 + Cl - + H 2 O Toxic compounds – Hypochlorous acid (OCl - ), and Singlet oxygen ( 1 O 2 )
  26. 26. Respiratory Burst Detoxification Reactions H 2 O 2 + O 2 Superoxide dismutase H 2 O + O 2 Catalase 2O 2 - + 2H + 2 H 2 O 2
  27. 27. Oxygen-Independent Killing in the Phagolysosome Effector Molecule Function Cationic proteins (cathepsin) Damage to microbial membranes Lysozyme Hydrolyses mucopeptides in the cell wall Lactoferrin Deprives pathogens of iron Hydrolytic enzymes (proteases) Digests killed organisms
  28. 28. Summary of Intracellular Killing Pathways Intracellular Killing Oxygen Dependent Oxygen Independent Myleoperoxidase Dependent Myleoperoxidase Independent
  29. 29. Nitric Oxide Dependent Killing IFN γ  TNF TNF Nitric Oxide Nitric Oxide
  30. 30. Non-specific Killer Cells <ul><li>NK and LAK cells </li></ul><ul><li>ADCC (K) cell </li></ul><ul><li>Activated macrophages </li></ul><ul><li>Eosinophils </li></ul><ul><li>They all kill foreign and altered self targets </li></ul>
  31. 31. Natural Killer (NK) cells <ul><li>also known as large granular lymphocytes (LGL) </li></ul><ul><li>kill virus-infected or malignant cells </li></ul><ul><li>identified by the presence of CD56 & CD16 and absence of CD3 </li></ul><ul><li>activated by IL2 and IFN- γ to become LAK cells </li></ul>
  32. 32. Lymphokine Activated Killer (LAK) cell IL2 IFN IFN IL2 kills malignant cells kills transformed and malignant cells
  33. 33. Regulation of NK Cell Function <ul><li>MHC I </li></ul><ul><li>KIR </li></ul><ul><li>KAR </li></ul><ul><li>KAL </li></ul><ul><li>No Killing </li></ul><ul><li>Killing </li></ul>
  34. 34. K Cells <ul><li>morphologically undefined </li></ul><ul><li>mediate ADCC </li></ul><ul><li>have Fc receptor </li></ul><ul><li>recognize antibody coated targets </li></ul><ul><li>could be NK cells (IgG), macrophages (IgG), eosinophils (IgE) or other cells (IgG) </li></ul>