Innate Immunity Flashcards
Response time: innate vs. adaptive immunity
Innate: minutes/hours
Adaptive: days
Soluble components of blood: innate vs. adaptive immunity
Innate: antimicrobial peptides, proteins, other mediators
Adaptive: antibodies and cytokines
Major cell types: innate vs. adaptive immunity
Innate: phagocytes (monocytes, macrophages, neutrophils), natural killer cells, epithelial and endothelial cells
Adaptive: T cells, B cells, antigen-presenting cells
Defining feature of pathogen
Directly or indirectly capable of causing damage to host cells or tissues
Innate immune system barriers
Skin Mucous membranes Antimicrobial peptides Degrading enzymes Iron chelators Normal flora Movement by cilia Acidic/dry environments
Defensins
Antimicrobial peptides
Disrupt structure and organization of microbial membranes using electrostatic features
Cathelicidins
Antimicrobial peptides
Disrupt membranes via electrostatic features
Where antimicrobial peptides are expressed
Sites of environmental contact Phagocyte lysosomes (especially macrophages and neutrophils)
Lysozyme
Enzyme that attacks cell walls of bacteria by breaking their carbohydrate chains
Lactoferrin
Protein found in neutrophil granules
Binds iron with high affinity: prevent viral and bacterial access to iron
3 phagocytic cells of innate immunity
Macrophage
Dendritic cell
Neutrophil
Phagocytosis steps
Bacterium attaches to membrane
Bacterium is ingested, forming phagosome
Phagosome fuses with lysosome
Bacterium is killed and then digested by lysosomal enzymes
Digestion products are released from cell
Reactive oxygen products
Used to kill and degrade phagocytosed particles
NADPH oxidase
Makes reactive oxygen products
Granulocytes
Act on extracellular pathogens too large to be phagocytosed
Release granules containing toxic products and enzymes
