Lecture 3- Immune mechanisms: pattern recognition and extracellular cascades

Question 1

4 components of am immune system

Answer 1

recognition, response, effect, integration

Question 2

difference between innate and adaptive receptors

Answer 2

innate or pattern recognition receptors- recognise/respond to agonists, e.g. toll-like receptors
adaptive- recognise/respond to antigens, e.g. antibodies, Tcell receptors

Question 3

what might trigger pattern recognition receptors

Answer 3

pathogen-derived molecules, or damage caused by pathogens- not sure exactly which
they can also detect damaged self cells, e.g. heat shock signals

Question 4

example of lectins in the lungs

Answer 4

surfactants SpA and SpD- bind pathogens in the lungs to help trigger cascades, also have some antimicrobial activity

Question 5

what is complement

Answer 5

a system of proteins which cleave each other as part of a cascade

Question 6

3 different complement activation pathways and the result of them

Answer 6

classical
lectin
spontaneous activation
all converge on C3 convertase being cleaved

Question 7

consequences of complement activation

Answer 7

chemosttraction
helping cells like macrophages become active more quickly
terminal complement cascade (punches a hole in the cell wall)

Question 8

spontaneous activation of complement

Answer 8

low-level cleavage of C3, leading to C3b binding to things and recruiting molecules- e.g. C3 convertase which can initiate a cascade

Question 9

distribution of PRRs within the body

Answer 9

all nucleated cells have them, but they are more abundant on cells like macrophages and dendritic cells

Question 10

example of a toll-like receptor and its action

Answer 10

TLR5- recognises flagellin
can integrate with other signals from other TLRs to identify a fairly large array of pathogens

Question 11

example of how TLR activation can cause problems

Answer 11

excessive response to TLR4 can lead to endotoxic shock

Question 12

example of how TLRs can trigger inflammation

Answer 12

TLRs stimulate the TF NFkB, which is involved in inflammation and can
can also help upregulate interferons
involve in cytokine production, also upregulation of TFs

Question 13

what are PAMPs and DAMPs

Answer 13

Pathogen-associated molecular pattern
Damage-Associated Molecular Patterns
TLRs recognise these

Question 14

how can co receptors aid TLR binding

Answer 14

at macrophages for example- LIPOPOLYSACCHARIDE BINDING PROTEIN LBP binds to a bacterial lipopolysaccharide, aids in TLR binding

Question 15

what is the recognition region in NOD-like receptors

Answer 15

leucine rich repeats

Question 16

example of other pattern recognition receptors

Answer 16

RIG-like and AIM

Question 17

how to PRRs aid viral response

Answer 17

help activate the ‘inflammosome’- cleavage of caspase I leading to cytokine activation- within this ‘inflammosome’, cells are more prone to apoptosis

Question 18

soluble vs cell-associated pattern recognition receptors- differences in function

Answer 18

soluble protects tissue fluid and body surfaces and activates extracellular cascades, cell-associated protects extracellular and intracellular compartments and activates cell signalling cascades

Question 19

differences in result from soluble vs cell-associated PRR

Answer 19

soluble- binds directly to pathogens/products, can help in cellular responses
cell-associated- generally change cell behaviour, e..g promoting phagocytosis or inducing expression of cytokines or antimicrobials