L12 Antigen Uptake Flashcards
What is antigen
anything with the potential for the immune system to recognise
two types of antigen
foreign (outside)
self (autoimmune disorders/ within body)
what is used for antigen recognition
TLR
complement and antibody
NOD-like recptors (NLR/ mannose receptors
what is used for antigen uptake and/or destruction
phagocytosis
pinocytosis
recpetor mediated endocytosis
autophagy (instracellular antigen)
three types of receptors that bind antigen
Fc
complement
mannose
how does the Fc receptor bind antigen
bind to antibody when it is in a complex with antigen
how do complement receptors bind antibody
C3b optinises antigen and forms complex
complex is recognises by complement receptor
how do mannose receptors bind antigen
microbes have mannose containing antigens which can bind to the mannose receptor
what does binding of antigen trigger?
phagocytosis
stages of phagocytosis
binding
uptake
phagosome formation
digestion of phagolysosome
what is autopahgy
similar to phagocytosis but for intracellular microbes
autopahgy process
intracellular pathogens coated with ubiquitin get encircled by phagophores to form autophagosome which fuses with lysosome and content is destroyed
what is receptor mediated antigen uptake
antigen is tagged by C3b or antibody which facilitates recognition and uptake by cell surface receptors
what are pattern recognition receptors (PRR)
recognise pathogen associate molecular patterns (PAMPs) + damage associated molecular patterns (DAMPs)
what are TLR a subset of ?
PRR
what do PRR promote
inflammation/ immune response
how are TLR found and NLR found
TLR: membrane bound
NLR: free floating in cytoplasm
what does the translocation of NF-KB to the nucleas induce?
inflammatory gene transcriptions
how do TLR signal
signal as dimers
ligand binds and two the TLRs recruit adaptor molecules which activate NF-KB which gets translocated for a gene to produce inflammatory response
effect of TLR signalling
increased cytokine secretion and phagocytic ability: increased pathogen clearance
triggers immune system reponses (fever etc)
increases immunostimulatory capacity of antigen presenting cells (DC)
what is the result of increased immunostimulatory DC
enhanced T cell stimulation and better memory responses
