Mucosal immunology

Question 1

What stem cell do B and T cells derive from

Answer 1

lymphoid stem cell

Question 2

What precursor are dendritic cells and macrophages derived from

Answer 2

myeloid progenitor

Question 3

What type of interactions is the GIT a site for

Answer 3

host-environment interactions

Question 4

What are the functions of the GI epithelial barrier

Answer 4

physical barrier
selectively permeable
secretory function

Question 5

What mediators are secreted from the GI epithelial barrier

Answer 5

cytokines
antimicrobial peptides
MUC proteins

Question 6

What controls which substances enter the epithelial barrier

Answer 6

cell junctions

Question 7

What structures do stem cells differentiate in the GI epithelial barrier

Answer 7

crypts

Question 8

How do crypts Renew

Answer 8

stem cells at the base
proliferate/differentiate whilst moving up
cells shed at the tip of villi

Question 9

How are crypts regulated

Answer 9

signalling molecules

Question 10

Which layer of the GIT exerts tolerance

Answer 10

lamina propria

Question 11

How is tolerance maintained in the GI mucosa

Answer 11

develop self-tolerance
exogenous tolerance
effective immune response

Question 12

what is exogenous tolerance

Answer 12

non-responsiveness to a variety of environmental antigens (food and microbes)

Question 13

what are the components of the epithelial barrier that ‘crosstalk’

Answer 13

microbiota
epithelial cells
immune cells

Question 14

what does the GI microbiota consist of

Answer 14

mucus with commensal bacteria

Question 15

How do microbes impact on intestinal epithelial cells

Answer 15

respond to microbes
express recognition receptors
stimulate cytokines which alter barrier permeability

Question 16

How is energy provided for the microbes in the barrier

Answer 16

intestinal epithelial cells produce mucins which are short chain fatty acids for microbes to break down

Question 17

How do immune cells impact on the intestinal epithelial cells/microbiota

Answer 17

promote barrier repair via cytokines
promote mucin production
impact on permeability

Question 18

What is the function of Peyer’s patches

Answer 18

allow efficient sampling of particulate antigens

Question 19

What are M cells

Answer 19

specialised and organised parts of the immune system in the gut

Question 20

How are antigens transported across the M cell

Answer 20

vesicles

Question 21

how are antigens in vesicles released from the M cell

Answer 21

released at the basal lamina

Question 22

What other methods can dendrite cells use to capture antigens

Answer 22

‘arms’ can extend across the epithelial layer
antigens captured from lumen of the gut

Question 23

What 3 signals determine T cell responses

Answer 23

MHC/peptide-TCR
CD80-CD28
Cytokines

Question 24

How does a T cell travel to the gut after being activated

Answer 24

through the blood

Question 25

How do activated T cells enter the gut

Answer 25

bind to MADCAM-1 on endothelium
gut endothelial cells express chemokines for direction

Question 26

Which immune cells balance gut homeostasis

Answer 26

T helper cells
T regulatory cells

Question 27

How are intraepithelial lymphocytes bound to the epithelium

Answer 27

expression of aeb7