1. The Immune System

2. First lines of defense: Skin Mucus Stomach acid Digestive enzymes

3. Innate Immunity Phagocytic cells –Leukocytes (“white cells”) –Lymphocytes (“lymph cells”) –Macrophages (“big eaters”) –Natural killer cells (attack infected or cancerous body cells)

4. Innate Immunity

12. Inflammation –Redness and swelling Interferon –Released by infected cells, signals neighboring cells to prepare for invasion

13. Acquired Immunity Lymphocytes –B cells and T cells Antibodies –Immunoglobulins

14. Antigens are foreign molecules that elicit an immune response Acquired Immunity

15. Antigens are foreign molecules that elicit an immune response. Acquired Immunity

16. B cells have antigen receptors that recognize intact antigens. B Acquired Immunity

17. T cells have antigen receptors for fragments of antigens. B T Acquired Immunity

18. Each lymphocyte recognizes one and only one antigen. B T Acquired Immunity

19. Lymphocytes are made in the bone marrow B cells mature in the bone marrow T cells go to the thymus before maturing. Acquired Immunity

20. Genes in lymphocytes are randomly, permanently rearranged to produce over ten million different antigen receptors The ones that react to “self” are destroyed. Acquired Immunity

21. Two kinds of immune response: Humoral Defends against toxins or pathogens outside of cells Cell-mediated or cytotoxic Destroys infected cells, cancer cells, and transplanted cells Acquired Immunity

22. Humoral Immune Response Here come the germs…

23. Humoral Immune Response Here come the germs…

24. Humoral Immune Response 1. A macrophage or a dendritic cell engulfs one of the invading bacteria

25. Humoral Immune Response 1. A macrophage or a dendritic cell engulfs one of the invading bacteria.

26. Humoral Immune Response 2. The macrophage displays broken up bits of the antigen bound to a major histocompatibility complex (MHC).

27. Humoral Immune Response 3. A helper T cell recognizes the antigen fragments and is activated

28. Humoral Immune Response 3. A helper T cell recognizes the antigen fragments and is activated

29. Humoral Immune Response 3. A helper T cell recognizes the antigen fragments and is activated

30. Humoral Immune Response 3. A helper T cell recognizes the antigen fragments and is activated.

31. Humoral Immune Response 4. A B cell also recognizes the antigen and binds to it

32. Humoral Immune Response 4. A B cell also recognizes the antigen and binds to it

33. Humoral Immune Response 4. A B cell also recognizes the antigen and binds to it.

34. Humoral Immune Response 5. An activated helper T cell binds to the B cell and secretes cytokines to activate it

35. Humoral Immune Response 5. An activated helper T cell binds to the B cell and secretes cytokines to activate it

36. Humoral Immune Response 5. An activated helper T cell binds to the B cell and secretes cytokines to activate it

37. Humoral Immune Response 5. An activated helper T cell binds to the B cell and secretes cytokines to activate it

38. Humoral Immune Response 5. An activated helper T cell binds to the B cell and secretes cytokines to activate it

39. Humoral Immune Response 6. The activated B cell divides to make two kinds of cells:

40. Humoral Immune Response -Plasma cells make antibodies

41. Humoral Immune Response Plasma cells (effector cells) make antibodies

42. Humoral Immune Response Memory cells wait for the next invasion.

43. Humoral Immune Response 7. Antibodies bind to antigens.

44. Humoral Immune Response There are four ways that antibodies work:

45. Humoral Immune Response There are four ways that antibodies work: neutralization

46. Humoral Immune Response There are four ways that antibodies work: neutralization

47. Humoral Immune Response There are four ways that antibodies work: neutralization

48. Humoral Immune Response There are four ways that antibodies work: agglutinization

49. Humoral Immune Response There are four ways that antibodies work: agglutinization

50. Humoral Immune Response There are four ways that antibodies work: agglutinization

51. Humoral Immune Response There are four ways that antibodies work: agglutinization

52. Humoral Immune Response There are four ways that antibodies work: agglutinization

53. Humoral Immune Response There are four ways that antibodies work: compliment fixation

54. Humoral Immune Response There are four ways that antibodies work: compliment fixation

55. Humoral Immune Response There are four ways that antibodies work: compliment fixation

56. Humoral Immune Response There are four ways that antibodies work: compliment fixation

57. Humoral Immune Response There are four ways that antibodies work: compliment fixation

58. Humoral Immune Response There are four ways that antibodies work: compliment fixation

59. Humoral Immune Response There are four ways that antibodies work: compliment fixation

60. Humoral Immune Response There are four ways that antibodies work: compliment fixation

61. There are four ways that antibodies work: opsonization Humoral Immune Response

62. There are four ways that antibodies work: opsonization

63. Humoral Immune Response There are four ways that antibodies work: opsonization

64. Humoral Immune Response There are four ways that antibodies work: opsonization

65. Humoral Immune Response There are four ways that antibodies work: opsonization

66. Humoral Immune Response There are four ways that antibodies work: opsonization

67. Humoral Immune Response There are four ways that antibodies work: opsonization

68. Humoral Immune Response There are four ways that antibodies work: opsonization

69. Humoral Immune Response There are four ways that antibodies work: opsonization

70. Humoral Immune Response There are four ways that antibodies work: opsonization

71. Humoral Immune Response There are four ways that antibodies work: opsonization

72. Humoral Immune Response There are four ways that antibodies work: opsonization

73. Cell Mediated Immune Response

74. Here come the germs…

75. Cell Mediated Immune Response A cell is infected

76. Cell Mediated Immune Response A cell is infected

77. Cell Mediated Immune Response 1. A cell is infected.

78. Cell Mediated Immune Response 2. Antigens are displayed on the cell surface bound to MHC.

79. Cell Mediated Immune Response 3. A cytotoxic T cell (“killer T cell”) binds to the antigens

80. Cell Mediated Immune Response 3. A cytotoxic T cell (“killer T cell”) binds to the antigens

81. Cell Mediated Immune Response 3. A cytotoxic T cell (“killer T cell”) binds to the antigens.

82. Cell Mediated Immune Response 4. Binding activates the T cell, which releases lytic enzymes.

83. Cell Mediated Immune Response 5. Lytic enzymes destroy the cell (“apoptosis”)

84. Cell Mediated Immune Response 5. Lytic enzymes destroy the cell (“apoptosis”)

85. Cell Mediated Immune Response 6. T cell can now attack other target cells.

86. Cell Mediated Immune Response Cancer cells will also display antigens that bind with killer T cells.

87. Immunity in Health and Disease

88. Active vs. passive immunity.

89. Immunity in Health and Disease Rejection of transplanted tissue

90. Immunity in Health and Disease Rejection of transplanted tissue Graft vs. host reaction.

91. Immunity in Health and Disease Allergies

92. Immunity in Health and Disease Autoimmune diseases

93. Immunity in Health and Disease Immunodeficiency diseases