ch 17.4

• Extravasation (Diapedesis)

  leukocytes can migrate from the circulatory system to the site of injury or infection
• pathogen-associated molecular pattern

  Peptidoglycan • Flagellin • LPS • Nucleic acids
• What is a pathogen-associated molecular pattern?

  molecular structures that are common, recognized by called pattern recognition receptors (PRR)
• example of PRR

  Toll-like receptors (TLR)
• are PRRS internal or external?

  both
• When a PRR binds a PAMP what happens?

  the production and secretion of antiviral interferons and cytokines
• phagocytosis

  a cell engulfs large particles or whole cells
• What types of enzymes are used to destroy the pathogen within the phagolysosome?

  Lysozyme • Phospholipase • Proteases
• 5 signs of acute inflammation

  erythema (redness), edema (swelling), heat, pain, altered function
• chronic inflammation

  prolonged immune response to residual pathogens
• chronic inflammation can lead to

  formation of granulomas

  Ex: Tuberculosis
• granulomas

  pockets of infected tissue surrounded by WBCs
• pyrogens

  certain infections can result in the formation of these, they alter the "thermostat setting" of the hypothalamus, causing fever
• ex. of pyrogens

  IL 1, IL 6, TNF
• benefits of a fever

  enhances innate immune defenses by stimulating leukocytes

  may inhibit growth of pathogen (most are mesophiles)
• potential complications of a fever

  immune response can be too strong, causing tissue and organ damage and, in severe cases, even death.
• crisis phase of fever

  fever breaks; vasodilation and sweating
• superantigen

  an excessive activation of T cell and of cytokines that overstimulates the inflammatory response.
• why are superantigens dangerous?\

  associated with very high, life-threatening fevers