Immunology

Question 1

Peyer’s patches are covered by an epithelial layer contains specialised cells called __________ which have characteristic membrane_______

Answer 1

M cells

ruffles

Question 2

What do M cells do?

Answer 2

These take up antigen by endocytosis and phagocytosis, the antigen is then transported across M cells in vesicles and released at the basal surface. The antigen is then bound by dendritic cells which activates T cells.

Question 3

What is special about dendritic cells in the gut?

Answer 3

These can extend processes across the epithelial layer to capture antigen from the lumen of the gut.

Question 4

T cells enter Peyer’s patches from ___1______ directed by ___2____ In Peyer’s patch if they encounter antigen they are transported across by ___3_____ and become activated by ____4____

Once activated the T cells drain via ___5___ lymph nodes to the ___6____ and return to the gut via the bloodstream. These activated T cells return to the lamina proprietary and epithelium of the small intestine due to the _____7_____ they express

Answer 4

1) blood vessels
2) homing receptors
3) M cells
4) dendritic cells
5) mesenteric
6) thoracic duct
7) homing receptors

Question 5

Describe intraepithelial T cells

Answer 5

These lie within the epithelial lining of the gut and are CD8+ and cells display antigens via MHC class 1. They kill infected epithelial cells via various mechanisms.

Question 6

What is the predominant immunoglobulin in the gut? Is this different from the normal systemic immune response?

Answer 6

It is the opposite

IgA predominates in the gut

Question 7

In the gut IgA exists as …

Answer 7

dimers

Question 8

What does the secretory component of IgA do>

Answer 8

gives IgA a longer half life in the lumen of the gut

Question 9

In the presence of commensal bacteria production of ______ inhibits dendritic cell maturation

Answer 9

PGE2
TGF-B
TSLP

Question 10

Immature dendritic cells give __1__ co-stimulatory signals and induce __2__ T cells to differentiate into ______3_____

Answer 10

1) weak
2) CD4
3) regulatory TH3 or Treg cells

Question 11

What type of immune disease is coeliacs?

Answer 11

It is a T cell mediated disease not antibody mediated

Question 12

What are the changes in the small intestine with gluten eating in coeliacs?

Answer 12

Get villi atrophy and loss of villi- small intestine with scalloping and increase in intraepithelial lymphocytes

Question 13

2 examples of inflammatory bowel diseases?

Answer 13

Chrons and Ulcerative colitis