Innate Immunity Flashcards
Innate immune responses are ….
Universal
What is inflammatory response?
Generic defence mechanism whose purpose is to localise + eliminate injurious agents + to remove damaged tissue components
What is process of inflammatory response?
Resident macrophage detect local bacteria + they respond by producing glycoprotein hormone => called cytokines + chemokines
They make endothelial walls much more permeable
Across endothelial walls, you can recruit neutrophil from blood stream
Therefore you enhance number of neutrophils present locally + they will help resolve that infection
What are cytokines and chemokines?
Are glycoprotein hormones that affect immune response
What do cytokines?
Act to modify behaviour of cells in immune response
What do chemokines?
Act as chemotatic gradients=> they create conc gradients which attract specific cell type to site of production/infection
Examples of PAMPs
Gram negative bacteria => lipopolysaccharide found in outer membrane
Gram positive bacteria => lipoteichoic acid, teichoic , peptidoglycan found in outer membrane
What are PRRs?
Host factors that specifically recognise a particular type of PAMP
Are germ line encoded
What are classes of PRRs?
Extracellular => recognise PAMPs outside of cell + trigger co ordinated response to pathogen
Intracellular => (cytoplasmic) they recognise PAMPs inside cell + act o coordinate a response to pathogen
Secreted => act to tag circulating pathogens for elimination.
What is complement?
A system of excreted proteins made in liver that recognise PAMPs on surface of microbes + decorated/ at them => microbes are cleared by phagocytosis, opsonised or they have holes punched in them
What are natural killer cells?
Lymphocyte like but larger with granular cytoplasm
Kill certain tumour + virally infected cells
Target cell destruction is caused by cytotoxic molecules called granzymes + perforins
How do natural killer cells kill virally infected cells?
Killer cell sneaks up on target cell
It binds to target cell + punch holes into it
It then injects little granules of proteases into it which destroys what’s inside cell
