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Chapter 22 Nonspecific Body Defenses and Immunity

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Presentation on theme: "Chapter 22 Nonspecific Body Defenses and Immunity"— Presentation transcript:

1 Chapter 22 Nonspecific Body Defenses and Immunity
Advanced Biology Chapter 22 Nonspecific Body Defenses and Immunity

2 Nonspecific – Innate Specific – Adaptive

3 Intact skin and mucosa

4 Phagocytes Other cells (inflammatory)

5 Specific Defense B Cells and T Cells

6 Functional System No Organs Trillions of Cells

7 Resistance to Disease

8 Nonspecific

9 Specific

10 Keratin provides a barrier – resistant to weak acids/bases and bacterial toxins

11 Acidic – pH 3-5, inhibits bacterial growth; sebum contains chemicals toxic to bacteria

12 Stomach – concentrated HCl and protein digesting enzymes

13 Saliva and lacrimal fluid contains lysozyme which destroys bacteria

14 Sticky mucus traps microorganisms

15 MACROPHAGES Derived from monocytes Free MAC wander all over

16 Kupffer cells -liver Alveolar cells – Lungs Permanent residents

17 WBC that can phagocytize

18 Neutrophils release defensins – kills everything around it, including itself

19 WBC Defend against parasitic worms by surrounding it and discharging enzymes

20 Some bacteria can replicate inside MACs, MACs are stimulated to release other chemicals (Nitric oxide)

21 Police the body Checks markers – releases cytolytic chemicals

22 Prevent Spread of damaging agents

23 Dispose of cell debris

24 Set stage for repair

25 Enhance the body’s nonspecific defenses by attacking microorganisms or hinder their ability to reproduce

26 Classical – Binding of antibodies
Alternative – Certain protein factors are initiated

27 Convergence on C3, Splitting it, C3a, C3b
Convergence on C3, Splitting it, C3a, C3b. Initiates events that cause lysis, promotes phagocytosis and enhances inflammation

28 Message to tell other cells there is a virus
Those cells synthesize “PKR” which interferes with viral replication

29 Pyrogens Pyro – fire

30 Causes liver/spleen to retain zinc/iron

31 Helps speed up metabolic rate of cells

32 Can denature bacterial enzymes

33 Chapter 22 Specific Body Defenses: Immunity
Advanced Biology Chapter 22 Specific Body Defenses: Immunity

34 Immune Response

35 Good

36 To mount an immune response is expensive. Lots of energy is required
To mount an immune response is expensive. Lots of energy is required. Being specific, energy is only expended when necessary.

37 Study of Immunity

38 Antigen-Specific Systemic Memory

39 Humoral (Antibody-mediated)
Cellular (Cell-mediated)

40 Intruders Not self

41 Immunogenicity – stimulate the proliferation of specific lymphocytes and antibody production

42 Reactivity – Ability to react with lymphocytes or antibodies

43 Part of antigen that is immunogenic
Binds to it

44 Self-antigen Major Histocompatibility Complex (MHC)

45 Class I MHC – All body cells
Class II MHC – Immune Response Cells

46 Antigen Presenting Cells (APC)

47 B Lymphocytes (Humoral)

48 T Lymphocytes (Cell mediated)

49 To be able to recognize a specific antigen

50 Eliminates them

51 Before meeting antigen
It is in your genes An antigen only determines which B or T cell will proliferate and attack

52 Engulfs antigen, shows it to a T cell

53 Chapter 22 Humoral Immune Response
Advanced Biology Chapter 22 Humoral Immune Response

54 Not a game show 

55 1st Encounter b/w immunocompetent lymphocyte and invading antigen

56 3 to 6 Days Takes time for B cells to differentiate

57 2ndry much faster, more prolonged and more effective. 2-3 day response
See pg 775

58 The capacity to produce a powerful 2ndry humoral response

59 When B cells encounter antigens and produce antibodies against them

60 Naturally acquired: During bacterial & viral infections

61 Artificially acquired: Through vaccine

62 Dead or attenuated (living but weakened) pathogens

63 Spare us from most of the symptoms
Provide functional antigenic determinates

64 No memory is established
Fetus to mother

65 Immunoglobulins

66 IgD – Attaches to B cells, activates B cells

67 IgM – Large, pentamer shape
IgM – Large, pentamer shape. Antigen receptive, 1st Ig released during primary response. Fixes and activates complement

68 IgG – Most abundant – 75-85%. Crosses placenta, protects against bacteria, viruses and toxins. Fixes complement.

69 IgA – Dimer (2), found in body secretions, helps prevent attachment of pathogens to epithelial cells

70 IgE – Stem region is bound to mast cells and basophils (allergies)

71 Antigen-Antibody complexes

72 Complement

73 Neutralization – blocks specific sites on viruses and bacteria

74 Agglutination – Clumping of cells

75 Precipitation – not rain.
Antigen molecules, not cells, are clumped together. See page 780.

76 Chapter 22 Cell-Mediated Immune Response
Advanced Biology Chapter 22 Cell-Mediated Immune Response

77 Microorganisms that slip inside body cells
Trying to avoid immune system

78 CD4 = T4, Helper Ts CD8 = T8, Cytotoxic Ts

79 Through processed parts on an APC

80 Provide means for signaling to immune system cells that infectious microorganisms are hiding in body cells

81 Step 1: Antigen Binding T cell antigen receptors, TCRs, bind to an antigen-MHC protein complex

82 Helper Ts bind to MHC II – w/help of APC
Cytotoxic Ts bind to MHC I – needs no APC

83 Step 2: Costimulation If bound to right costimulator (protein, chemicals), stimulation (proliferation) occurs. W/O right match, T cell activity is stopped

84 Mediators involved in cellular immunity

85 Lymphokines – released by activated T cells
Monokines – secreted by MACs

86 Interleukin 1 & 2 – IL 1 released by MACs tells T cells to liberate IL 2, which encourages T cells to divide more rapidly.

87 Tumor Necrosis Factor (TNF) – enhances nonspecific cell killing

88 Perforin/lymphotoxin are cell toxins that T cells can release
Perforin/lymphotoxin are cell toxins that T cells can release. Lethal Hit.

89 Gamma Interferon – enhance killing power of MACs

90 Regulatory cells Interact with B cells

91 Major function is to chemically or directly stimulate proliferation of other T cells and B cells that have already become bound to antigen

92 W/O helper Ts, there is no immune response!!

93 Killer T cells They can directly attack and kill other cells

94 Main target is virus infected cells, also tissue cells that have been infected, parasites, cancer cells, foreign cells introduced by blood transfusions or organ transplants

95 Help stop immune response after antigen has been destroyed

96 Promote allergic reactions

97


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