1. Immune system Chapter 43

2. Pathogen: Infectious agent Innate immunity: Nonspecific Acquired immunity: Specific Previous exposure

3. Acquired Immunity Active Disease Vaccine Transfer of lymphocytes from a donor (bone marrow transplant) Passive Maternal antibodies Immunoglobulins (gamma globulins)

4. Defense First line –Skin Second line –Cell counterattack Third line –Immune response (antibodies) –Specific

5. First-line Skin 1. Impenetrable barrier 2. Oil & sweat glands Skin pH--3-5 3. Sweat contains lysozyme Enzyme digests bacterial walls 4. Prevents water loss

6. Skin

7. First line Lysozyme in saliva Stomach acid Digestive enzymes in gut Airway mucous Cilia in airways Acidic urine

8. First line

9. Trachea

10. Second line Invaders Lymphatic system Defense cells Adenoids, tonsils Thymus, spleen Lymph nodes, lymph capillaries & ducts

11. Lymphatic system

12. Second line WBC Antimicrobial proteins Inflammatory response

13. Second line Leukocytes (WBC) Circulating in body 1. Macrophages (monocytes) Kill invaders by ingesting them Phagocytosis Ingestion

14. Fig. 43-3 Microbes PHAGOCYTIC CELL Vacuole Lysosome containing enzymes

15. Second line 2. Neutrophils Most abundant WBC Phagocytosis Release chemicals--kill bacteria Also kills other neutrophils

17. Second line 3. Eosinophils WBC Low phagocytic activity Parasite defense

18. Second line Antimicrobial proteins 1. Complement system Proteins found in plasma Attack bacterial or fungal cell walls Cause cells lysis Signals other defense responses

19. Second line 2.Interferons Paracrine polypeptide Protect cells in area of virus Prevent viral replication Cancer defense

20. Second line 3. Natural killer cells Kills cells infected by a virus Help fight cancer cells

21. Second line Inflammatory response Local, non-specific Histamines & prostaglandins Vasodilation Increased blood flow to area Edema or swelling WBC (phagocytic), pus formation Shock, systemic

22. Second line

23. Inflammatory response Elevated temperature (fever) Interleukin-1 Released by Macrophages Directs hypothalamus to increase temp Helps stimulate defense response

25. Third line Specific response Lymphocytes T-cells---cellular response B-cell---humoral response Antibodies

26. Third line Antigen Foreign molecule Epitope Antigen determinant Located on surface Causes a specific immune response

27. Third line Self-versus-nonself recognition Genes code for specific proteins Major Histocompatibility Complex proteins MHC proteins Cell recognition Glycoproteins on surface of cells

28. Third line B-cell lymphocytes Made & develops in bone marrow Becomes a plasma cell Produce antibodies in response to specific antigens Immunoglobulins (Ig) Antibodies Humoral immunity

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30. Third line B-lymphocyte structure Antigen receptor Specific Plasma membrane

31. Third line Light chains 2 short polypeptides Heavy chains 2 identical long polypeptides 4 chains held together by disulfide bond Forms Y-shaped molecules

32. Fig. 43-9a Antigen- binding site Antigen- binding site Disulfide bridge Variable regions Constant regions Transmembrane region Plasma membrane Light chain Heavy chains Cytoplasm of B cell (a) B cell receptor B cell V V C C V V CC

33. Fig. 43-10 Antigen-binding sites Antigen- binding sites Epitopes (antigenic determinants) Antigen Antibody B Antibody C Antibody A CC C V V V V C

34. Antibodies Plasma cells release antigen receptor Specific for antigens Arms of the Y shaped molecule Have different aa sequences

35. Antibodies IgM first response Aggregation of complement proteins IgG major form, second response Stimulates phagocytosis by macrophages IgD receptors for antigens on B cells IgA Present in breast milk, mucous, saliva Provide protection to newborns

36. Antibodies IgE Release histamines Bind to mast cells Insert heavy chain into mast cells Initiate inflammatory response Presence of antigens Vasodilation

37. Antibodies

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39. Third line T-cell lymphocytes Made in bone marrow Processed in thymus gland Regulate immune responses Attack cells with specific antigens Cell-mediated immunity

40. Fig. 43-9b Antigen- binding site Variable regions Constant regions Transmembrane region Plasma membrane T cell  chain  chain Disulfide bridge Cytoplasm of T cell (b) T cell receptor C C V V

41. Third line T-cells 1. Helper T cells (CD4) Initiate response based on antigens 2. Memory T cells Remember previous antigens

42. Third line 3. Cytotoxic T cell (CD8) Lyse cells infected by virus 4. Suppressor T cells Turn off immune response

43. Third line response Antigen Macrophage process antigen Secrete cytokines (interleukins or interferons) Stimulates T helper cells

44. Third line response Recognize antigens Antigen receptor on T-cells Bind to antigens Triggers T-cytotoxic cells, T-memory cells Cytotoxic cells destroy infected cells Stimulates B cells

45. Third line response Antigen receptor on B-cell Binds foreign antigen Triggers formation of a clone of plasma cells Clones produce antibodies Antibodies bind invading antigen Prevent affects of antigen Destruction or blocks effect

47. Immune response Macrophage ⇓ Helper T-cell ⇙ ⇘ B-cell Cytotoxic T-cell ⇙ ⇘ ⇙ ⇘ Plasma Memory Memory Cytotoxic cells cells cells T-cells ⇓ Antibodies

48. T-cells Cytotoxic T-cells Attack transplants (skin grafts) Considered foreign tissue Destroy cancer cells Interferon (lymphomas, renal Ca, melanoma, Kaposi’s sarcoma and Breast Ca) Interleukin (tx cancer)

49. B-cells Primary immune response First exposure Lasts about 2 weeks Memory cells are also produced during the first exposure Secondary immune response Activates memory cells Response faster & lasts longer

50. Immune System Summary First line Skin, cilia, enzymes, pH of skin Second line WBC (macrophages, neutrophils, natural killer cells, eosinophils) Antimicrobial proteins Inflammatory response

51. Immune System Summary Third line Lymphocytes (B & T) Antibodies (immunoglobulins) IgM, IgG, IgA, IgE, IgD

52. Monoclonal antibodies Antibodies specific for one antigen Cell cultures produce large quantities Use in lab tests Pregnancy tests Antibody to HCG (human chorionic gonadotropin)

54. HIV Human immunodeficiency virus Attacks + destroys CD4+ T-cells T-cells secrete a suppressing factor Blocks other T-cells Infects macrophages & brain cells

55. Autoimmune diseases Systemic Lupus Rheumatoid arthritis Hashimoto thyroiditis

56. Allergy Allergens (antigens) Release IgE Binds mast cells & basophils Stimulates release of chemicals Histamine Drop in BP

57. Allergy Anaphylactic shock Widespread histamine response Death Bee stings or peanuts or penicillin Contact dermatitis Delayed response Poison ivy, poison oak

59. Blood types (ABO) Blood type Surface antigensAntibodies A A anti B B B anti A AB none O anti A & B

60. ABO

63. Rh factor