Gut Immunology

Question 1

Describe the features of the Intestinal-Epithelial barrier

Answer 1

• Has tight junctions
• Goblet cells secrete mucins
• Paneth cells secrete lysozyme rich granules

Question 2

What is MALT? What are the subtypes of MALT?

Answer 2

Mucosal Associated Lymphoid Tissue

NALT (nasal)
BALT (bronchus)
GALT (gut)

Question 3

What % of lymphocytes are located in MALT?

Answer 3

75%

Question 4

As you travel down the digestive system, does the commensal flora become more aerobic or anaerobic?

Answer 4

More anaerobic

Question 5

The Immune Response can be divided into what two arms?

Answer 5

Innate Immune Response

Adaptive Immune Response

Question 6

How does the Innate Immune Response recognise bacteria?

Answer 6

Via bacteria’s Pattern Recognition Receptors i.e. LPS, Peptidoglycan

Question 7

How does the Adaptive Immune Response recognise bacteria? Specifically T cells and B cells?

Answer 7

Via bacteria’s Antigen-specific receptors

T cells recognise Peptide / MHC complex
B cells recognise 3D Structure

Question 8

What does Th2 secrete?

Answer 8

IL-4 and IL-5 (against extracellular pathogens)

Question 9

What does Th1 secrete?

Answer 9

IFN-gamma (against intracellular pathogens)

Question 10

What does Th17 secrete?

Answer 10

IL-17 (against extracellular bacteria / fungi)

Question 11

What are the three Organised tissues of GALT?

Answer 11

• Peyer’s patches
• Isolated lymphoid follicles
• Mesenteric lymph nodes

Question 12

What are the two Scattered lymphoid cells of GALT?

Answer 12

• Lamina Propria Leukocytes (LPL)

- Intraepithelial Lymphocytes (IEL)

Question 13

Where are Peyer’s Patches found?

Answer 13

In the small intestine

Question 14

Where are Isolated Lymphoid Follicles found?

Answer 14

In small and large intestine

Question 15

What is the role of M cells (Microfold cells)?

Answer 15

M cells transport antigens from the lumen to the cells of the immune system

Question 16

State the names of some pathogens which target M cells to gain entry into the sub-epithelial space

Answer 16

Poliovirus
Reovirus
Salmonella
Shigella
Yersinia

Question 17

In Intestinal inflammation, how might the balance of Effector T cells and Regulatory T cells be disrupted?

Answer 17

Too many effector cells

or

Too little regulatory cells

Question 18

What is the dominant antibody in the Mucosal Immune System?

Answer 18

Dimeric IgA linked by a J chain

Question 19

In patients who are IgA deficient patients, what Ig can take over and replace it?

Answer 19

IgM (pentameric)

Question 20

Which TLR of the Dendritic cell recognises LPS?

Answer 20

TLR4

Question 21

Which TLR of the Dendritic cell recognises Peptidoyclan?

Answer 21

TLR2

Question 22

Which TLR of the Dendritic cell recognises Flagellin?

Answer 22

TLR5

Question 23

What two genetic mutations predispose you to Crohn’s Disease?

Answer 23

NOD2

IL-23

Question 24

What is the mechanism of action of Azathioprine?

Answer 24

Inhibits Purine synthesis, thus is an Immunosupressant

Question 25

What is the mechanism of Infliximab and Adalimumab?

Answer 25

anti-TNF-a antibody (biological agent)