lec 10-11 innate/adaptive immune response

Question 1

innate immune response

Answer 1

non-specific
immediate
no immunological memory
includes physical barriers such as skin, chemicals in the blood, and immune system cells that attack foreign cells in the body.

Question 2

adaptive immune response

Answer 2

acquired immune system

specific to antigen
lag time from exposure to response
immunological memory after exposure

composed of highly specialised, systemic cells and processes that eliminate pathogens or prevent their growth

Question 3

innate humoral response

Answer 3

chemicals circulating in the blood
complement system
membrane attack complex

Question 4

adaptive cell-mediated response

Answer 4

mediated by t-cells

- regulate activity of b-cells

Question 5

professional phagocytes

Answer 5

monocytes
macrophages
neutrophils
tissue dendritic cells
mast cells

Question 6

when bacteria are taken up by an endosome

Answer 6

pH of phagosome drops
environment becomes more hostile for bacteria
- signalling pathways triggered
- fusion with lysosome to form phagolysome

Question 7

phagolysosome

Answer 7

lysosome contains potent chemicals to destroy bacteria e..g lysozyme (antibacterial agent)

Question 8

action of lysozyme on phagolysosome

Answer 8

vesicle ruptures and releases

damage signal recruits other immune cells

Question 9

how do innate immune cells detect viral infection

Answer 9

pattern recognition receptors (PRRs)

• present on cell surface or in intracellular compartments

Question 10

types of PRRs

Answer 10

TLRs
NLRs
receptor kinases

Question 11

how do TB pathogens prevent normal immune pathways

Answer 11

use mannose receptors
no inflammatory response initiated
sits in early endosome
produce proteins that prevent fusion with lysosome
no phagolysosome formation

Question 12

toll-like receptors

Answer 12

membrane spanning
both intra and extra cellular portions
come as pairs (dimeric)
e.g. TLR1 pairs with TLR2
recognise and bind to ligands of microbes

recognise PAMPs

Question 13

TLRs activate immune response when they bind

Answer 13

recruit adaptor proteins within cytosol

antigen-induced signal transduction pathway

Question 14

nod-like receptors

Answer 14

cytoplasmic bound - not membrane
pick up bacteria if escaped from endosome
recognise presence of PAMPs
NOD - nucleotide-binding oligomerization domain
LRRs - leucine rich repeats

Question 15

Pathogen Associated Molecular Patterns -PAMPs

Answer 15

activate innate immune responses
- protect host from infection

elevate protein levels
transduce signals through cell to increase transcription of cytokine

Question 16

examples of PAMPs

Answer 16

flagellin
peptidoglycan
lipoprotein

Question 17

bacteria aim to escape the vacuole

Answer 17

bacteria secrete toxin called cytolysin - lyses membrane

cytolysin is cholesterol dependent - attacks hosts membranes

Question 18

listeria secretes listeriolysin extracellularly

Answer 18

lower pH causes more listeriolysin to be produced
phagosome ruptures
bacteria becomes intracellular and spreads
recruits actin tails for movement
produces a phospholipase

Question 19

process of Salmonella

Answer 19

use TLRs to ensure they get to protected environment:

• taken up and recognised by TLRs
• bacteria hijacks TLRs
• signalling creates acidic pH of vacuole

reaches salmonella-containing vacuoles(SCV) - protective niche

then secrete proteins into the cell to prevent further damage:

secreted effector proteins
prevent fusion with lysosome

Question 20

process of shigella

Answer 20

• enters M cells (sensory gut molecules)
• enters into macrophage
• induces cell death (secretion of effector proteins into cytoplasm -T3SS)
• recognised by intracellular NLRs
• plasma membrane ruptures
• bacteria escape and enter neighbouring cells

Question 21

T3SS

Answer 21

type 3 secretion system

used by pathogenic gram-ve bacteria
detect eukaryotic organisms
secrete effector proteins that help bacteria infect cells

Question 22

autophagosome formation

Answer 22

LC3 (myosin light chain 3) and ubiquitination come together on membrane

membrane ‘isolation’ sac elonagtes anf close forming double membrane vesicle

Question 23

autolysosome formation

Answer 23

• outer membrane fuses with a lysosome
• degradation of cytoplasmic contents
• broken down products can be re-used e.g. amino acids

Question 24

autophagy

Answer 24

intracellular degradation system

targets portions of cytoplasm and delivers cytoplasmic constituents to the lysosome

beneficial for clearing infectious diseases

Question 25

control of autophagy

Answer 25

Type 3 secretion system - T3SS | IcsB - intracellular spread

Question 26

pro-inflammatory cytokines

Answer 26

interleukins interferons tumour necrosis factor (TNF-alpha)

Question 27

process of phagocytosis

Answer 27

bacteria taken up by phagocytosis bacteria destroyed within phagolysosome phagocytes act as APCs - antigen presenting cells parts of bacteria (antigens) appear on the surface of the phagocyte presented to a helper T cell helper T cell activated

Question 28

antigens present to..

Answer 28

MHC molecules

Question 29

tri-molecular complex

Answer 29

key in recognition made up of : - MHC - peptide - T cell receptor

Question 30

where are peptides held

Answer 30

in the grooves of the MHC I and II molecules

Question 31

CD1 molecule

Answer 31

``` MHC-like structure present glycolipids (not peptides) to natural killer t cells ```

Question 32

CD8+ T cells recognise antigens presented by ...

Answer 32

MHC I molecules

Question 33

CD4+ t cells recognise antigens presented by ...

Answer 33

MHC II molecules

Question 34

structure of MHC I

Answer 34

2 polypeptides and a beta-2 microglobulin component

Question 35

antigens presented by MHC I originate from the ...

Answer 35

cytosol

Question 36

antigens processed by proteosomes in the cytosol are loaded...

Answer 36

through the endoplasmic reticulum onto antigen presenting cells (MHC I)

Question 37

when CD8+T cells are stimulated...

Answer 37

memory cells are activated | CD8 releases perforin molecules and granzymes which attack infected host and destroy

Question 38

2 killing mechanisms by cytotoxic t cells

Answer 38

perforin CD95 or FasL pathway

Question 39

perforin pathway

Answer 39

perforin molecules delivered from cytoplasmic granules fuse with membrane of APC pores form allowing granzymes to enter infected cell cause apoptosis

Question 40

CD95 or FasL pathway

Answer 40

``` recognition system of cell death molecules FasL expression increases on CTL binds to Fas on the APC Generation of proteases apoptosis initiated ```

Question 41

structure of CD4 cells

Answer 41

2 polypeptides groove for peptide to sit in no beta-2 microglobulin lots of co-receptors in addition to tri-molecular complex

Question 42

CD4 T cells recognise antigens that originate directly from ...

Answer 42

the phagosome

Question 43

CD4 T cells

Answer 43

helper T cells produce many cytokines - depending on how they are activated help Cd8 T cells affect B cells - antibody production

Question 44

production of cytokines and chemokines

Answer 44

modulates an immune response

Question 45

after exposure to TB, if innate immunity is inadequate then

Answer 45

infection occurs

Question 46

if TB infection occurs and adaptive immunity is inadequate then

Answer 46

latent infection occurs | bacteria is contained in a granuloma

Question 47

process of infection with TB

Answer 47

TB taken up by macrophages immune cells recruited by chemokines e.g. neutrophils innate granuloma - TB is surrounded by immune cells inflammatory cytokines recruit D cells e.g. TNF-alpha immune granuloma - chronic granuloma

Question 48

chronic granuloma

Answer 48

fibrotic capsule | surrounded by fibroblasts

Question 49

if CD4 levels are low...

Answer 49

then probably immunocompromised

Question 50

proteins in membranes of vacuoles

Answer 50

MHC I and II