Immunology

Question 1

which part of the GI tract plays the largest role in immunity?

Answer 1

Colonic mucosa

Question 2

how does colonic mucosa identify pathogens

Answer 2

detects and recognises luminal contents, then differentiates between antigens of ‘good bacteria’ and pathogens.

Question 3

what happens if the immune system is responsive to self- antigens

Answer 3

autoimmune disease

Question 4

what must immune system not be responsive to

Answer 4

• own antibodies
• food
• good bacteria/ normal flora

Question 5

function of epithelial layer of gut in terms of immunity

Answer 5

tight junctions enable epithelial layer to act as a barrier, which decides what goes from lumen side into the host

Question 6

function of mucous layer in lumen

Answer 6

physical barrier keeping microbes from host cells

Question 7

examples of antigen presenting cells:

Answer 7

• dendritic cells

- macrophages

Question 8

innate immune response

Answer 8

initial immune response at site of insult

Question 9

adaptive immune response

Answer 9

more specialised, developed over time (e.g. from previous infection)

Question 10

cells involved in innate immune response

Answer 10

granulocyte
mast cell
monocyte
dendritic cell
macrophage 
natural killer cell

Question 11

cells involved in adaptive immune response

Answer 11

T cells
b cells
plasma cells

Question 12

function of cytokine proteins in immune response

Answer 12

decide what happens to cells, and how T cells should differentiate

they are produced by cells and act on cells

Question 13

Describe Peyers Patches

Answer 13

specialised lymphocyte aggregations - sample whats in the lumen by reaching across epithelium to take a bit of the protein. they well then pass these on to antigen presenting cells, who pass them to T cells to make a response decision

Question 14

describe macrophages

Answer 14

• phagocytic
• first line of defence in the gut
• sample particular antigens

Question 15

function of dendritic cells in mucosal immunity

Answer 15

• can give rise to different T cell responses (tolerance vs. immunity)
• distinguish cell markers
• DC presents antigens to indecisive T cells

Question 16

what do dendritic cells become when they undergo maturation after picking up something

Answer 16

Potent Antigen Presenting Cells (APC)

Question 17

explain gut homeostasis with regards to T cells

Answer 17

T helper cells and T regulatory cells must remain in balance to prevent disease

Question 18

2 examples of when normal immune homeostasis goes wrong

Answer 18

1. inflammatory bowl disease

2. coeliac disease