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Flashcards in Mucosal Immunology Deck (95)
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1

What is the name of the specific immune follicles in the Large intestine?

Lymphoid follicles

2

WHat is the name of the specific area related to immunity in the small intestine?

Peyer's Patch

3

What is concentrated in muscosal sites?

Specialised lymphoid tissue

4

Why is the immune system highly vulnerable to infection

Due to the fragility and permeability of the tract. Any food we ingest could be contaminated and require an immune response to remove the antigen

5

What 5 types of cells are found in the monolayer separating the microbiota from the lamina propria

Enteroabsorptive cell
goblet cells
neuroendocrine cells
paneth cells
M cells

6

What is the benefit of the villi and crypts

THey provide a large surface area for antigens to interact

7

What is the purpose of the Paneth cells

They are defensins

8

What occurs in the Peyer's Patches?

Antigen sampling and immune activation

9

What types of cells is the large intestine mostly made up of?

Crypts (not villi), enterocytes and lots of goblet cells and mucus

10

Which has the higher bacterial load? the small or large intestine

Large intestine

11

Why do enterocytes have a much more important contribution to antimicrobial peptide production in the large intestine?

There are no Paneth cells in the large intestine

12

Where do natural killer T cells have a more significant role to play?

In the colon

13

What are the main secretors of antimicrobial peptides

The Paneth Cells

14

What 3 types of cells capture, initiate the local immune response and carry out effector functions to clear any infection?

Intestinal epithelial associated - innate immunity, antigen capture and effector function
Peyer's patches and lymphoid follicles - antigen capture and initiation
Lamina propria - effector cells (remove the danger and repair any damage)

15

How do dendritic cells capture antigens across the epithelium?

They can extend their processes to capture antigens from the lumen of the gut

16

What are the direct antigen sampling organisms of the gut?

The Peyer's patches

17

Describe the structure of Peyers patchs

covered by an epithelial layer containing specialised cells (M cells) which have characteristic membrane ruffles

18

What is situated directly below an M Cell?

Dendritic cells

19

Describe the steps of the M cells

Uptake of antigen by endocytosis and phagocytosis
Transporation of antigen across the M cells in vesicles released at the basal surface
Antigen is bound to dendritic cells, activating T cells

20

What is the major effector molecule in the gut called?

IgA

21

What type of cells enter the Peyer's patches form blood vessels?

T cells

22

What happens to the T cells in the Peyer's patch when an antigen is transported across M cells?

They become activated by dendritic cells

23

What is the make up of the humoral intstinal response?

80% IgA
15% IgM
5% IgG

24

As peristalsis occurs, what happens to IgA

It is moving and being produced continuously

25

How does IgA move accross the membrane from the lamina propria to the lumen?

Endocytosis then transcytosis

26

What is the function of IgA cells

They bind and neutralise pathogens and toxins to prevent damage to the epithelial cells

27

What 3 ways can IgA work>

Bind to the antigen in the gut or on the mucus layer
Neutralise antigens in endosomes
Export toxxins and pathogens from the lamina propria whilst being secreted

28

What molecule takes over this role in patients who are IgA deficient?

IgM

29

How frequently are intraepithelial lymphocytes found?

1 in every 10 epithelial cells

30

What anchors intraepithelial lymphocytes in the epithelium

Expression of Alpha E: Beta 7 integrin

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