Body Defenses and Immunity

1. Body Defenses and Immunity Ch 21

2. Hansen’s Disease (Leprosy) Mycobacterium leprae

3. Bubonic Plague Yersinia pestis January 1900

4. Antibiotic Resistance • Antibiotics- drugs that fight infection caused by bacteria • Antibiotic resistance- when bacteria change eliminating the effectiveness of the drug designed to cure or prevent infection. • How does it happen? • Bacteria survive antibiotic control and continue to multiply into resistant strains.

5. Timeline of Antibiotic Resistance • 1929- Alexander Fleming discovers the 1st antibiotic (penicillin) • 1942- penicillin available through mass production • 1954- 2 million lbs of antibiotics produced in the U.S. annually • 1960’s- various resistant strains emerging due to abused antibiotic use • Today- 50 million lbs of antibiotics produced in the U.S. annually

6. Antibiotic Resistance How it happens

7. Diseases that have Exhibited Antibiotic Resistance • Typhoid fever • Vancomysin/Glyco peptide intermediate Stapylococcus aureus (VISA/GISA) • Vancomycin-resistant Enterococci • Tuberculosis • Gonorrhea • Head lice • Malaria • Methicillin- resistant Staphylococcus aureus (MRSA) • Streptococcus pneumoniae

8. Antibiotic Resistance Antibiotic Resistance on Factory Farms Fish Vaccination

9. The Nature of Disease • Pathogenic Organisms • Genetic Disorders • Toxic Chemicals • Other Environmental Factors • Physical Damage to Organs • Nutritional Disorders

10. Types of Pathogenic Organisms • Viruses • Bacteria • Protozoan • Fungi • Animal • Parasites

11. Mechanisms of Disease by Pathogens • Utilization of host nutritional resources • Physical damage to host tissues • Production of toxic substances • Chromosomal and gene damage • Body cells behave abnormally

12. envelope capsid nucleic acid Viruses

13. cell wall plasma membrane cytoplasm circular DNA Bacteria

14. Defense Mechanisms • External defense • Internal Defense • Immune Defense

15. 1st Line of Defense • Skin acts as barrier to microbes and viruses • - sweat has a low pH • Mucus traps foreign particles • Saliva cleanses oral cavity • Tears • - Lysozyme has antimicrobial action • Gastric stomach acid

16. epidermis sebaceous glands sweat gland Body Coverings: The Skin

17. mucus cilia columnar epithelium Body Coverings: Mucous Membranes

18. 2nd Line of Defense • Phagocytic cells (WBCs) • N L M E B • Natural Killer (NK) Cells: attack virus infected cells • Inflammatory Response • Antimicrobial proteins • Lysozyme • Interferon • Antibodies

19. Nonspecific Phagocytosis Neutrophils Monocytes Eosinophils

20. Mechanism of Phagocytosis Mechanism of Phagocytosis Macrophage

21. Natural Killer Cells • Innate immunity • Cytoxic • Activated by presence of interferon • Kills cancer and virus-infected cells before the adaptive immune system is activated.

22. Inflammatory Response Histamine & prostaglandins released Capillaries dilate Clotting begins Chemotactic factors attract phagocytic cells Phagocytes consume pathogens & cell debris

23. Antimicrobial Protein • INF • - Secreted by infected cells • Complement System • - 20 plasma proteins • - MAC http://www.youtube.com/watch?v=IWMJIMzsEMg

24. Characteristics of Immunity • Recognition of self versus non-self • Response is specific • Retains a “memory” allowing an accelerated second response • Can respond to many different materials • Involves lymphocytes and antibodies

25. Types of Acquired Immunity

26. Active Immunity • The production of antibodies against a specific disease by the immune system. • Naturally acquired through disease • Artificially acquired through vaccination • Vaccines include inactivated toxins, killed microbes, parts of microbes, and viable but weakened microbes. • Active immunity is usually permanent

27. A vaccinated person has a secondary response based on memory cells when encountering the specific pathogen. • Routine immunization against infectious diseases such as measles and whooping cough, and has led to the eradication of smallpox, a viral disease. • Unfortunately, not all infectious agents are easily managed by vaccination. • HIV vaccine in the works

28. Passive Immunity Passive Immunity- Protection against disease through antibodies produced by another human being or animal. • Effective, but temporary • Ex. Maternal antibodies • Colostrum.

29. Passive immunity can be transferred artificially by injecting antibodies from an animal that is already immune to a disease into another animal. • Rabies treatment: injection with antibodies against rabies virus that are both passive immunizations (the immediate fight) and active immunizations (longer term defense).

30. Immune System Response to Antigens • Humoral Immunity • Involves antibodies (secreted from B cells) dissolved in the blood plasma. • Demonstrated as a immune response using only the blood serum. • Defense against bacteria, bacterial toxins, & viruses.

31. Immune System Response to Antigens • Cell-Mediated Immunity • Involves the activities of specific white blood cells (T cells). • Defense against cancer cells, virus-infected cells, fungi, animal parasites, & foreign cells from transplants.

32. Lymphocyte Formation

33. B Cells • Mature in bone marrow • Involved in humoral immunity • Once activated by antigen, proliferate into two clones of cells: plasma cells that secrete antibodies and memory cells that may be converted into plasma cells at a later time

34. antibodies B Cells

35. B Cells B Cells

36. antigen Activation of B Cells by Antigen

37. Clonal Selection

38. antibodies Clonal Selection plasma cells memory cells

39. Overview of Immune System Responses

40. Humoral Immune Response first exposure to antigen A antibody concentration time (days)

41. Humoral Immune Response first exposure to antigen A primary response: concentration of anti-A antibody antibody concentration second exposure to antigen A time (days)

42. secondary response: concentration of anti-A antibody first exposure to antigen B second exposure to antigen A Humoral Immune Response antibody concentration time (days)

43. first exposure to antigen B Humoral Immune Response primary response: concentration of anti-B antibody antibody concentration time (days)

44. Antibodies constitute a group of globular serum proteins called immunoglobins (Igs). • A typical antibody molecule has two identical antigen-binding sites specific for the epitope that provokes its production.

45. antigen binding sites antigen light chains heavy chains Antibody Molecule

46. Mechanisms on Antibody Action • Precipitation of soluble antigens • Agglutination of foreign cells • Neutralization • Enhanced phagocytosis • Complement activation leading to cell lysis • Stimulates inflammation

47. The binding of antibodies to antigens to form antigen-antibody complexes is the basis of several antigen disposal mechanisms.

48. The classical complimentary pathway, resulting in lysis of a target cell

49. Immunoglobin Classes • IgM • 1st response to antigen • Effective in agglutination • Can’t cross placenta • IgD • B cell activation • Can’t cross placenta • IgG • Most common form • Crosses blood vessels • Crosses placenta (passive immunity to fetus) • IgE • Histamine reactions and allergies • IgA • Secreted from mucus membranes • Prevents attachment of bacteria to epithelial surface • In colostrum

50. T Cells • Mature in thymus • Involved in cell-mediated immunity • Activated when another cell presents antigen to them • Several types of T cells: cytoxic T cells, helper T cells, suppressor T cells, and memory T cells