pattern recognition receptors Flashcards
how to handle bacteria and fungi
phagocytosis and killing
how to handle virurses
cellular shut-down, self-sacrifice, cellular resistance
problems with immunity
Immunity can take a long time but infections arrive quickly and unpredictably
Adaptive immunological memory is highly specific, cross-reacting or self-targeting
There a lot of bacterial species and viruses out there
Only vertebrates have an adaptive system; there must be other effective immune systems
what does the PRR family consist of
Secreted and circulating PRRs
Cell-associated PRRs (more traditional receptors)
what are Secreted and circulating PRRs
Antimicrobial peptides secreted in lining fluids from epithelia
Lectins and collectins (carbohydrate-containing proteins that bind carbohydrates or lipids in microbe walls.
what do Secreted and circulating PRRs do
Activate complement, improve phagocytosis
what are cell-associated PRRs
Receptors that are present on the cell membrane or in the cytosol of the cells
Recognise a broad range of molecular patterns
TLRs are the main family (toll-like receptors)
what does recognition of microbes depend on
depends on seeing ancient, conserved features of them
describe pattern recognition
Families of receptors exist to detect microbes in fluids, cell surfaces and compartments, and intracellularly
Obvious roles in pathogen responses
Additional roles in homeostasis and damage recognition
what are blood neutrophil numbers dependent on
may be dependent upon TLR4 signalling, independent of LPS (lipopolysaccharide) in homeostasisw
what are TLR’s adapted to recognise
a range of endogenous damage molecules, which may share characteristics of hydrophobicity
what does TLR signalling by cellular damage do
activates immunity to initiate tissue repair and perhaps enhance local antimicrobial signalling
describe PRRs and disease
Recognition of host molecules in autoimmune disease
Failure to recognise pathogens or increased inflammatory responses
what is Recognition of molecular pattern key for
key to survival and successful establishment of commensal microbiome.
describe Pattern recognition receptor system
highly conserved systems of immunity, evolved to recognise unchanging patterns.
