1. Immune system
Chapter 43

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

3. Defense First line Second line Third line Skin Cell counterattack
Immune response (antibodies)

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

5. Skin

6. First line Lysozyme in saliva Acid in stomach Digestive enzymes in gut
Mucous in airways
Cilia in airways
Acidic urine

7. First line

8. Trachea

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

10. Lymphatic system

11. Second line
WBC
Antimicrobial proteins
Inflammatory response

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

13. Microbes PHAGOCYTIC CELL Vacuole Lysosome containing enzymes Fig. 43-3
Figure 43.3 Phagocytosis

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

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

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

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

19. Second line 3. Natural killer cells
Kill cells that are infected by a virus
Help fight cancer cells

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

21. Second line

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

24. Third line
Specific response
Lymphocytes (B-cell orT-cell)
Antibodies

25. Third line Antigen Molecule that causes a specific immune response
Foreign to body
Located on surface
Epitope
Antigen determinant

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

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

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

31. Antigen- binding site Antigen- binding site V Disulfide bridge V V V
Fig. 43-9a
Antigen-
binding
site
Antigen-
binding site V
Disulfide
bridge V V V
Variable
regions C C
Constant
regions C C
Light
chain
Transmembrane
region
Figure 43.9 Antigen receptors on lymphocytes
Plasma
membrane
Heavy chains
B cell
Cytoplasm of B cell
(a) B cell receptor

32. Antigen-binding sites
Fig
Antigen-
binding
sites
Epitopes
(antigenic
determinants)
Antigen-binding sites
Antibody A
Antigen V V
Antibody C V V C C C C
Figure Epitopes (antigenic determinants)
Antibody B

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

34. 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

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

36. Antibodies

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

39. Antigen- binding site Variable regions V V Constant regions C C
Fig. 43-9b
Antigen-
binding
site
Variable
regions V V
Constant
regions C C
Transmembrane
region
Figure 43.9 Antigen receptors on lymphocytes
Plasma
membrane
 chain
 chain
Disulfide bridge
Cytoplasm of T cell
T cell
(b) T cell receptor

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

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

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

43. 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

44. 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

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

47. 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)

48. 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

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

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

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

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

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. HIV

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57. AIDS Acquired immunodeficiency syndrome Opportunistic infections
Pneumocystis carinii
Kaposi’s sarcoma
Neurological damage
Physiological wasting

58. Autoimmune diseases Systemic Lupus Rheumatoid arthritis
Hashimoto thyroiditis

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

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

62. Blood types (ABO) Blood type Surface antigens Antibodies A anti B B
anti A AB
none O
anti A & B

63. ABO

66. Rh factor