T1 L10: Mucosal immunology

Question 1

What is mucosa-associated lymphatic tissue (MALT) divided into?

Answer 1

BALT: bronchus-associated lymphatic tissue
GALT: gut-associated lymphatic tissue

Question 2

What is microbiome?

Answer 2

Totality of genes of organisms in the gut

Question 3

What is micrbiota?

Answer 3

microorganisms of the gut

Question 4

What are the effects of having a diet high in phytochemicals, omega-3 fatty acids, fibre, and prebiotics?

Answer 4

Causes enhanced mucus secretion and increased antimicrobial peptides so there is a regulated immune response and a functional intestinal barrier

Question 5

What are the effects of having a diet high in sugar, fat, emulsifiers, meat protein, and low dietary fibre?

Answer 5

Causes enhanced mucus degradation and reduced antimicrobial peptides so there is a proinflammatory immune response and a dysfunctional intestinal barrier

Question 6

What is a prudent diet?

Answer 6

Rich in fibre which supports a healthy gut microbiota

• Increased mucus production
• Increased expression of tight junction proteins

Question 7

What is a western diet?

Answer 7

Low in fibre so diversity of bacteria is reduced

• More often chronic inflammation
• leakiness because there aren’t as many tight jap junctions

Question 8

What is the function of Paneth cells?

Answer 8

Produce human defensin 5 and 6 (HD5 and 6) precursor and trypsin which activates HD5 and HD6 by proteolytic cleavage

Question 9

What is the function of Goblet cells?

Answer 9

They produce mucus and a physiochemical barrier

Antimicrobial peptides and antibodies of IgG and IgA and dispersed in the mucus

Question 10

What is the function of M cells?

Answer 10

They transport antigens from gut lumen to subepithelial lymphoid structures

Question 11

What are Peyer’s patches?

Answer 11

Lymphoid follicles located in the lamina propria and submucosa in the GI tract

Question 12

Where are the 2 areas where the greatest amount of lymphoid tissue is found in the GI tract?

Answer 12

The Oropharynx (Waldeyer’s ring) and the terminal ilium

Question 13

Where are Peyer’s patches found?

Answer 13

In the distal ilium in areas of follicle associated epithelium (FAE)

Question 14

What do follicular areas of Peyer’s patches contain?

Answer 14

• Lymphoid follicles with a germinal centre containing proliferating B-lymphocytes
• Follicular dendritic cells fixing antigen on surface
• Macrophages

Question 15

What do interfollicular areas and the subepithelial dome of Peyer’s patches contain?

Answer 15

• B-cells
• T-cells
• Macrophages
• Dendritic cells

Question 16

How do B-cells enter Peyer’s Patches?

Answer 16

Through high endothelial venules (HEV’s) as well as naive T-cells

Question 17

What is hyper IgM syndrome?

Answer 17

When class switch can’t happen because there is a mutation causing lack of CD40 on T-cells

It’s X-linked so affects mostly males

Question 18

What is released in the gut that encourages IgA growth?

Answer 18

Nitric oxide and TGF-beta

Causes IgA to be the antibody primarily produced instead if IgG

Question 19

What is the dome of Peyer’s patches covered in?

Answer 19

M-cells which deliver gut antigens into the Peyer’s patches

Question 20

What is cell homing also known as?

Answer 20

Cellular recirculation patterns