1. immunity


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a brief description on immunity

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1. immunity

  1. 1. IMMUNOLOGY Aruni Puthuppally Asst Professor Noorul Islam Dental College Trivandrum
  2. 2. Immunologys The group of cells, tissues and molecules that are associated with the resistance to microbial invasion is called immune system.s The coordinated reaction of immune system towards the microbes is known as immune response.
  3. 3. s The immune system is made up mainly of lymphoid organs and reticuloendothelial cells.s The RE cells consisting of lymphocytes and plasma cells are the key mediators of the immune response.
  4. 4. MALTThe Organs of the Immune System
  5. 5. The Cells of the Immune System
  6. 6. s Lymphocytes originated from thymus are known as T-lymphocytes and are responsible for Cell Mediated Immunity (CMI).s Lymphocytes originated from bone marrow are known as B-lymphocytes and are responsible for Antibody Mediated or Humoral Immunity (AMI).
  7. 7. CMIAMI
  8. 8. Antibody Mediated Immunitys Antibody mediated immunity (AMI) provides primary defense against most extracellular bacterial pathogens and their toxins.s Abs are present in blood, lymph and mucus secretions.s B cells are responsible for the production of Abs.s AMI helps in defense against viruses that infect through the RT and GIT.s It participate in the pathogenesis of immediate type 1,2 and 3 HS and certain autoimmune diseases.
  9. 9. Cell Mediated Immunitys CMI protects against infection by fungi, viruses and facultative intracellular bacterial pathogens.s CMI participate in the rejection of homograft and GVH reaction.s It provides immunological surveillance and immunity against cancer.s CMI mediates the pathogenesis of delayed type 4 HS and certain autoimmune diseases.
  10. 10. Immunitys Host resistance against microorganisms & other substances.s Immune response : Rxn of the body against foreign antigen.
  11. 11. ImmunityInnate ½ Acquired
  12. 12. Innate Immunitys Inborn resistance presents Genetic and constitutional make ups Does not require prior exposures Not modified significantly by repeated exposure
  13. 13. Innate ImmunitySpecies Racial Individual
  14. 14. Plant Virus XPhysiological and Biochemical Differences
  15. 15. Innate ImmunitySpecies Racial Individual
  16. 16. More su sceptibl e for TBX Algerian sheep
  17. 17. Innate ImmunitySpecies Racial Individual
  18. 18. Show similar sensitivity or resistance Do not show such similarity
  19. 19. Factors influencing level of immunity Factors influencing level of immunity m es xtre o E Tw
  20. 20. Components of Innate ImmunityPhysical barriers Chemical barriers Biological barriers
  21. 21. Physical Barriers1. Skin and Mucous Membranes Form a ‘wall’ between deep tissues and pathogens.2. “Flushing” mechanisms a. Salivary flow  Prevents bacterial overgrowth b. Coughing & Sneezing  Clears respiratory tract c. Urination  Flushes the urinary tract d. Lacrimation  Cleanses eyes e. Ciliary action  Expels bacteria
  22. 22. Chemical Barriers1. pH of body fluids  Inhibits growth of many pathogens2. Lysozyme  Breaks down cell walls of bacteria3. Interferon  Inhibits viral replication
  23. 23. Biological Barriers1. Natural resistance  Species resistance to microbes2. Normal flora  Competes with invaders3. Inflammation  Localizes & destroys pathogens4. Complement  Cell lysis and phagocytosis5. Phagocytosis  Engulfment of pathogens
  24. 24. Mechanisms of Innate Immunity A. Non immunological defenses B. Immunological defensesA B • Antibacterial agents in blood & tissues• Epithelial surface • Cellular factors• Microbial antagonism • Fever • Acute phase proteins • Inflammation
  25. 25. Immunologic Defensess Antibody mediated - IgM, IgG, IgAs Cell mediated - T lymphocytess Phagocytosis - Neutrophils, Macrophagess Complement - Lysis & enhances phagocytosis
  26. 26. Acute Phase ProteinsActivate alternate pathway of complement • C reactive protein • Mannose binding protein • Alpha – 1- acid glycoprotein • Amyloid P
  27. 27. Fevers A rise in temperature following infection is a natural defense mechanism.s Pathogens like Treponema pallidum will be destructed at high temperature.s It stimulate the production of interferon and aids recovery from viral infections.
  28. 28. Opsonization – a process that facilitates phagocytosis by coating antigens with opsonin (Eg. antibody and C3b)
  29. 29. InflammationImmunological response to tissue injury.Non-specific defense mechanism.Vascular changes & recruitment of neutrophils & macrophages.
  30. 30. Classic features of Inflammation¢ Calor (Heat)• Dolor (Pain)• Rubor (Redness)• Tumor (Swelling)
  31. 31.  Cells & Proteins in Inflammatory Reactionss Cells s Specific proteins • Phagocytes • CRP • Monocyte- • Mannose binding protein Macrophage • Amyloid protein • Natural killer cell • Prostaglandins
  32. 32. Cytokines:Biologically active proteins that are released during inflammationDuring inflammation, they: 1) Affect the local microcirculation by causing vasodilation and increased vascular permeability 2) Attract immune system cells to the site and activate cells involved in tissue repair.
  33. 33. Chemotaxis – migration of cells in response to concentration gradients of certain factors Diapedesis – movement of blood cells between endothelial cells lining blood vessels
  34. 34. Neutrophil Extravasation In InflammationBlood flow
  35. 35. ImmunityInnate Acquired ½
  36. 36. Acquired Immunitys The resistance that an individual acquires during life.s ↑ es dramatically with subsequent exposure to the same Ag.s Immune response primarily refers to acquired immunity.
  37. 37. rison Co mpa Innate Immunity Acquired Immunity “Line of defense” “First” “Second” Specificity General SpecificImproved response No Yes upon re - exposure Immunological No Yes memory Cells Phagocytes, NK Lymphocytes (B,T) cells
  38. 38. Acquired Immunity Active PassiveNatural Artificial Natural Artificial
  39. 39. Types of Acquired immunitys Active – Resistance developed as a result of antigenic stimuluss Passive – Resistance that is transmitted in a readymade form
  40. 40. Active Immunitys Induction of immunity by infection or with a vaccine is called Active Immunity.s Natural : By a clinical or inapparent infection.s Artificial : By vaccines.
  41. 41. Passive Immunity The resistance that is transmitted to a recipient in a readymade form. Here the recipient’s immune system plays no active role. There is no latent period, but immunity is transient. Non-immune individual can be made immune by transferring serum or lymphocytes from an immune individual. Serum constituents (antibodies) and lymphocytes are involved in immunity.
  42. 42. Passive Immunitys Natural : Mother to fetus.s Artificial : Administration of antibodies. Ex: ATS, TIGs Uses of passive immunity : • Temporary protection of non-immunised patients • For treatment of particular infection • For suppression of active immunity, Eg: RhIg
  43. 43. Comparison of active & Passive immunity Active Immunity Passive Immunity Produced actively by host’s immune system Received passively,No active host participn Induced by infection or by immunogens Readymade antibody transferred Durable, effective protection Transient, less effective Immunity effective only after lag period Immediate immunityImmunological memory present No memory Booster effect on subsequent dose Subsequent dose less effective ‘Negative phase’ may occur No negative phaseNot applicable in the immunodeficient Applicable in immunodeficient
  44. 44. Adoptive immunitys Extract of immunologically competent lymphocytes: Transfer factor, are injecteds Application- Lepromatous leprosy
  45. 45. Local immunitys Achieved by administration of live vaccines • Eg: Polio vaccines Secretory IgA produced locally by plasma cellss These IgA are responsible for this
  46. 46. Herd immunitys Refers to overall level of immunity in a communitys Relevant in controlling epidemic diseases Eradication of communicable diseases depends on the development of a high level of herd immunity
  47. 47. Immunology Your Skin Your T-cellPathogen Your WBC Pathogen
  48. 48. Immunology Your Skin Your T-cellPathogen Your WBC Pathogen
  49. 49. Granulocytes Agranulocyte Agranulocyte T-Cells B- Cells NK Cells
  50. 50. Factors influencing level of immunity Factors influencing level of immunity m es xtre o E Tw
  51. 51. Components of Innate ImmunityPhysical Barriers Chemical Barriers Biological Barriers
  52. 52. Innate immunityAcquired immunityActive immunityPassive immunityFactors influencing innate immunityComparison – active and passive immunityMechanism of innate immunity
  53. 53. Local immunityHerd immunityAdoptive immunityVaccinesCell Mediated ImmunityAntibody Mediated Immunity
  54. 54. In severe combined immunodeficiency, a persons ability to fightinfections is severely impaired. This condition has been dubbed "bubbleboy disease" and became widely known during the 1970s with the case of David Vetter, who lived for 12 years sealed in a plastic, germfree environment.
  55. 55. Thank you