Review of Innate Immunity Flashcards
What does adaptive immunity involve?
β very specific recognition of an infectious agent (usually a protein)
What does innate immunity involve?
β no specific antigen recognition
β recognition of broadly conserved features of different classes of pathogens
What are the 6 components of innate immunity?
β Phagocytosis β The inflammatory response β cytokines, interferons and antimicrobial peptides (AMPs) β complement β intrinsic defences 'the hostile cell' β NK cells
What immune feature do all multicellular organisms have in common?
β means to recognise and phagocytose debris and infected cells
What cells is phagocytosis carried out by in vertebrates?
β dendritic cells
β macrophages
β neutrophils
What cells do most of the phagocytosis at the site of infection?
β neutrophils
What do neutrophils do in chronic inflammation?
β they do a lot of tissue damage during chronic inflammation
What two things does phagocytosis do?
β clears pathogens
β presents peptides on MHC
What does phagocytosis promote?
β development or reactivation of the adaptive immune response
How is material destroyed in phagocytosis?
β in lysosomes
Where are macrophages found?
β in tissues
What can trigger macrophage activation?
β captured material
What do activated macrophages produce?
βcytokines and chemokines to stimulate both innate and adaptive immune responses
What do the products of activated macrophages trigger and what does this promote?
β the inflammatory response and can promote a local antimicrobial state
What is the main purpose of macrophages?
β clear and recruit other cells to the site of infection
What is the purpose of the inflammatory reponse?
β localise and eliminate injurious agents and to remove damaged tissue components
What are the 4 things that occur during the inflammatory response?
β Enhanced permeability of endothelial cells and extravasation
β neutrophil recruitment into the cell
β enhanced cell adhesion
β enhance clotting
What are cytokines and chemokines?
β Glycoprotein hormones that affect the immune response
What do cytokines do?
β act to modify the behavior of cells in the immune response
What are most cytokines called?
β Interleukins
What do chemokines do?
β act as chemotactic factors
β they create concentration gradients which attract or occasionally repel specific cell types to a site of production/infection
What does a macrophage secrete when it is infected?
β IL-8
What does TNF alpha do?
β opens the endothelium and triggers an anti-viral response
What 2 cells types is IL-1 produced by?
βmacrophages and keratinocytes
What is the effect of IL-1 and IL-6?
β induces acute-phase protein secretion
What 2 cell types produce IL-6, IL-8, and IL-12?
β macrophages and dendritic cells
What is the effect of IL-8?
β chemoattractant for neutrophils
What is the effect of IL-12?
β Diverts the immune response to type 1
β proinflammatory cytokine secretion
What are the 4 ways in which phagocytes know what to phagocytose?
β detecting phosphatidylserine
β scavenger receptors
β toll-like receptors
β passive sampling