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Immune System

Immune System. Disease. Any change in the body not due to injury that disrupts homeostasis Pathogens = Sickness makers How do we know pathogens make you sick?. Koch’s Postulates. The suspected causal organism must be constantly associated with the disease.

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Immune System

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  1. Immune System

  2. Disease • Any change in the body not due to injury that disrupts homeostasis • Pathogens = Sickness makers How do we know pathogens make you sick?

  3. Koch’s Postulates • The suspected causal organism must be constantly associated with the disease. • The suspected causal organism must be isolated from an infected organism and grown in pure culture. • When a healthy susceptible host is inoculated with the pathogen from pure culture, symptoms of the original disease must develop. • The same pathogen must be re-isolated from the organism infected under experimental conditions.

  4. Lyme Disease Risk

  5. Lyme Disease Etiology • Allen Steere (1975) Yale University • 39 children from Lyme Connecticut • All had pain and joint inflammation • All had insect bites and rashes • Dr. Willy Burgdorfer found spirochete in ticks • Steere found same bacterium in his patients

  6. Non-Specific Immunity 1st Line of Defense • Skin • Mucous membranes • Saliva • Mucus • Nasal hair • Tracheal cilia • Stomach acid • Sweat • Tears

  7. Non-Specific Immunity 2nd Line of Defense • Phagocytes • Natural killer (NK) cells • Inflammatory response • Pyrogens (Reset thermostat in hypothalamus) • Complement proteins • Interferon (Prevents viral replication) • Lysozyme (Pokes holes in bacterial cell walls)

  8. Non-Specific Immunity • Complements identify antigen • Granulocytes attack antigen creating pus • Macrophages perform phagocytosis on bacteria

  9. Inflammatory Response • Damaged tissue releases histamine • Capillaries become “leaky” • Blood flow increases to area • Clotting factors and phagocytes released into the wound • Phagocytes engulf bacteria, cellular debris, & dead cells • Macrophages release cytokines which attract immune system cells • Platelets seal the wound with a clot

  10. Specific Defenses • Humoral immunity – immunity against pathogens in body fluids (blood and lymph) • Immune response carried out by lymphocytes • Cell-Mediated immunity – Antibody production

  11. Antibodies • Antibody = a protein that helps to destroy pathogens • Substrate specific • Cause agglutination which attracts phagocytes • Made by plasma cells • Plasma cells made by b-lymphocytes

  12. Humoral Immunity

  13. Antibodies IgM IgG IgA

  14. Cell Mediated Immunity • Active immunity - vaccination with antigen (lasts for years) • Passive immunity – transferring antibodies from one person to another (lasts several weeks)

  15. Dr. Edward Jenner

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