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NONSPECIFIC HOST DEFENSES

NONSPECIFIC HOST DEFENSES. Innate (nonspecific immunity) Defenses present at birth. Innate immunity. Characteristics Present at birth Always present and available to provide rapid responses to disease Does not involve specific recognition of a microbe Acts on all microbes in the same way

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NONSPECIFIC HOST DEFENSES

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  1. NONSPECIFIC HOST DEFENSES Innate (nonspecific immunity) Defenses present at birth

  2. Innate immunity • Characteristics • Present at birth • Always present and available to provide rapid responses to disease • Does not involve specific recognition of a microbe • Acts on all microbes in the same way • No memory response

  3. First line defense Intact skin Mucous membranes and secretions Normal flora Second line defense White blood cells Inflammation Fever Antimicrobial substances Nonspecific resistance

  4. Skin

  5. Skin • Intact skin prevents microbes from entering the skin • Break in the skin can allow microbes to enter and cause disease • Loss of this barrier protection can lead to serious infection

  6. Mucous Membranes • Barrier protection • Not as strong as the skin • Lining of the respiratory tract, GI tract and genitourinary tract • Mucous secretion keeps surfaces moist

  7. Epithelial lining of the trachea

  8. Lacrimal apparatus

  9. Lacrimal apparatus • Protection for the eye • Tears are produced by the lacrimal gland • Tears and their washing action helps keep the surface of the eye free from bacterial accumulation • LYSOZYME is also found in tears and this enzyme has anti-bacterial action as well

  10. Granulocytes Neutrophils Eosinophils Basophils Agranulocytes Monocytes Macrophages Lymphocytes White Blood Cells

  11. White Blood Cells

  12. WBC numbers • Never – neutrophils 60-70% • Let – lymphocytes 20-25% • Monkeys – monocytes 3-8% • Eat – eosinophils 2-4% • Bananas - basophils .5-1%

  13. Phagocytosis (cell eating)

  14. Basophil • .5-1% of white cells • Not a phagocytic cell • Release histamine • Inflammation reaction

  15. Lymphocytes • T cells and B cells • Antibody production and cell-mediated immunity

  16. Phagocytosis

  17. Stages of phagocytosis • Ingestion • Formation of phagosome • Formation of phagolysosome • Digestion • Discharge

  18. Stages of phagocytosis

  19. Inflammation • Defensive local response by body to tissue damage • Inflammation is characterized by: • Redness • Pain • Heat • Swelling

  20. Fever • Systemic response to injury • Increase in body temperature as response to infection • Shivering with fever is the results of a new higher set point for body temperature • Fever is a defense against disease • Fever may help to activate body defense mechanisms

  21. Antimicrobial Substances • Complement • Interferon

  22. Complement • Defensive system of over 30 proteins that are made in the liver and circulate in the blood and tissues • Activation of complement destroys microbes by lysis, inflammation, and phagocytosis • Complement proteins act in a CASCADE, that is, one reaction triggers another

  23. Complement

  24. Interferon • Classes of anti-viral proteins • First discovered in the mid 1950’s • Produced by cells such as lymphocytes, macrophages and fibroblasts AFTER viral stimulation - RNA viruses • Interfere with viral multiplication

  25. Interferon • Three classes of interferons • Alpha - leukocytes • Beta - fibroblasts • Gamma - lymphocytes (T cells) • Produced after viral infection • Induces near by cells to produce anti-viral to protect against the virus • Currently produced by recombinant DNA technology

  26. Magic Bullet? • Interferon has several limitation to its use • Short term effectiveness • Side effects • High concentrations toxic to heart, kidney, liver, bone marrow • Currently used to treat Hepatitis C • Used in Eastern Europe and Russia to treat colds and flu but this is widely accepted elsewhere

  27. Interferon

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