Lecture 3: Inflammation and the Innate Immune Response Flashcards
What are the 3 lines of defense/phases of the immune response?
Barriers
Innate
Adaptive
Describe barriers:
➢ First line of defense
➢ Block or destroy pathogens when they enter the body
➢ i.e. skin, mucosal membranes
Describe the innate immune response:
➢ Non-specific attack by molecules, cells, and mechanisms
➢ Triggered by cell or tissue damage
➢ i.e. Inflammation
Describe the adaptive immune response:
➢ APC activate T and B cells
➢ Specific antibody production and coordinated cell attack
Explain what Rubor is and its cause:
Redness
Cause:
➢ Increased blood flow accounts for the redness
➢ Vasodilation occurs soon after the injury = accelerated blood flow
➢ Histamine causes vasodilation
Explain what Calor is and its cause:
Heat
Cause:
➢ Increase in blood flow also causes an increase in heat
Explain what Dolor is and its cause:
Pain
Cause:
➢ Swelling puts pressure on local pain receptors = pain and loss of function
Explain what Tubor is and its cause:
Swelling
Cause:
➢ Following the increase in blood flow, the microcirculation becomes more permeable
➢ Allows the leakage of protein-rich fluid into the interstitial space
➢ Leukotrienes produced by the mast cells increase vascular permeability
What does Histamine do?
Found in many cell types, causes vasodilation
What do Kinins do?
Released from damaged tissues, recruits more phagocytes
What do Prostaglandins do?
Intensify the effects of Histamine and Kinins, help phagocytes out of the blood and into the tissues
What do Leukotrienes do?
Promote adherence of phagocytes and increase vascular permeability
Which cytokines secreted by macrophages cause inflammation?
IL-1β TNF-α IL-6 CXC18 IL-12
How do tissue resident macrophages cause inflammation?
They release cytokines that increase the permeability of blood vessels and chemokines that attract other phagocytes
________ differentiate into macrophages and move towards the site of damage
Monocytes
__________ released due to inflammation cause the __________ cells in the blood vessels to express _________.
Chemokines
Endothelial
Selectins
Explain leukocyte rolling:
Leukocytes roll along the endothelial walls due to weak interaction with selectins and their ligands and integrins (on the cell), eventually, they bind stably (stable adhesion due to chemokine signalling) and squeeze between the cells to exit the vessel
WBC can only exit through the _______
veins
What are the 5 stages of phagocytosis?
- Chemotaxis
- Adherance
- Ingestion
- Digestion
- Excretion
What happens during the chemotaxis stage?
- Phagocytes move up the chemokine concentration gradient to reach the site of inflammation
What happens during the adherence stage?
- Membrane of the phagocyte makes contact with the pathogen
What happens during the ingestion stage?
- Pseudopods envelop the pathogen
- A vesicle forms around the pathogen = phagosome
What happens during the digestion stage?
- Phagosome fuses with a lysosome =pagolysosome
- Enzymes from the lysosome digest the pathogen
What happens during the excretion stage?
- After digestion, the phagolysosome is filled with fragments and is called a residual body
- Residual bodies migrate to the cell surface and are exocytosed
