Inflammation part 2 Flashcards
what are the 5 steps of the inflammatory response
5 RS
recognition of injurious stimulus recruitment of leukocytes removal of the causative agent regulation of the response resolution of the response and repair
what is the first line of defence in recognising different pathogen
macrophages and dendritic cells
how many kinds of receptors do dendritic and macrophage cells have
several different types to recognise different pathogen associated molecular patterns (PAMPS)
what does PAMPS stand for
pathogen associated molecular patterns
what are TLRs
toll like receptors- a class of proteins which recognises PA,PS
what are TLRs made from
multiple leucine rich repeats
where are TLRs found
membrane associated proteins- some are found on the surface and some are endocytic vesicles
what do the endocytic TLrs detect
where they survey degraded particles of substances taken in by endocytosis
what does TLR5 recognise
flagellin- highly conserved constituent of bacterial flagella
what do bacterial genomes contain
highly methylated CPG oligonucleotides MOTIFS
what does TLR9 detect
highly methylated CPG oligonucleotides MOTIFS once it has been degraded in the lysosome
where is TLR9 found
in the endocytic vesicle
what TLRS are a dimer
TLR2 + TLR6
TLR1 +TLR2
what does TLR2 and TLR6 detect
diacylipopeptide
what do TLR1 and TLR2 detect
triacylipopeptide
what does TLR4 detect
lipopolysaccharide- found in gram -ve bacteria
where is TLR3 AND TLR7 found
inside the endocytic vesicle
what does TLR3 recognise
double stranded RNA
what does TLR7 recognise
single stranded RNA
What happens when TLR is activated
it sends a signal to the nucleus which activates transcription factors
where do viruses exist and replicate
in the cytosol
what are the two classes of receptors which recognise pathogens in the cytosol
NOD- nucleotide oligomerazation domain proteins
RNA helices domain and caspase recruitment domain- more importantly RIG-I
what does the NOD2 protein detect
bacterial proteoglycans of intracellular bacteria
what happens when the NOD2 receptor recognises its ligand
sends a signal to nucleus to activate transcription
what is the ligand of the NOD2 protein
muramyl dipeptide
what does RIG-I detect
double stranded rna which sends a signal to the nucleus
what happens when RIG-I is activated
sends a signal to the nucleus to produce type 1 interferon
what re the functions of a leukocyte
phagocytosis
secretion of microbicidal substances to remove extracellular inflammatory agent
release of extraceullar tramps eg NETosis
amplification of inflammatory response
what is NETosis
neutrophil-death through a different pathway than apoptosis or necrosis.
what can the secretion of microbicidal substances to remove extracellular inflammatory agent lead to
tissue damage
what is the key function of macrophages
to secrete pro inflammatory cytokines which then recruit further cells at the site of inflammation
what are the key players in amplification of inflammatory response
macrophages
what is NET
neutrophil extracellular traps
what is phagocytosis
recognition and attachment
engulfment
killing and degradation
what are microbes or dead cells recognised by in phagocytosis
direct or by opsonins
how does killing and degradation occur
by enzyme degradation and products of respiratory burst such as NO AND ROS
what is ROS in phagocytosis
reactive oxygen species
what is at the respiratory burst
a burst of activity where you get ROS AND NO into the intracellular space which are toxic molecules helps to kill pathogens
what is superoxide produced from
the oxidation of NADPH carried out by phagocyte oxidase
which enzyme carries out the oxidation of NADPH
phagocyte oxidase
what can superoxide be covered to
hydrogen peroxide and then hypochlorite by myeloperoxidase
what enzyme converts super chloride into hydrogen peroxide and hypochlorite
myeloperoxidase
WHERE IS MYELOPEROXIDASE FOUND
in cells with the myeloid lineage
what produces peroxynitrite
superoxide and nitric oxide
what can ROS cause
killing microbes but can also damage host cell injury
what is the pathological effects of ROS
LIPID PEROXIDATION- membrane damage
PROTEIN MODIFICATIONS- breakdown and misfolding
DNA DAMAGE leading to mutations
what enzymes are secreted from neutrophils azurophilic granules
neutrophil elastase
proteinase 3
cathespin G
WHAT EXTRACELLULAR ACTIVITY CAN OCCUR
Secretion of microbicidal substances: Secretion of enzymes release of lysosomal enzymes secretion of chemokines and cytokines NETosis
what is NETosis
the generation of neutrophil extracellular traps
what is NETosis stimulated by
microbes and inflammatory signals