Mucosal Immunity

Question 1

T and B cells are found in 3 places in the GALT:

Answer 1

1. Epithelium.
2. Lamina propria.
3. Peyer’s Patch.

Question 2

Defensins are secreted in the GALT by:

Answer 2

1. Paneth cells.

2. Epithelial cells.

Question 3

Gut outer mucus layer:

Answer 3

• Non sterile.
• Degrading mucus.
• Microbes utilize mucin carbs for energy.

Question 4

Gut inner mucus layer:

Answer 4

• Relatively sterile.

- Rich in antimicrobial molecules (defensins).

Question 5

M cells:

Answer 5

Epithelial cells that can transport antigen from lumen to cells in the lamina propria.

Question 6

Peyer’s Patches:

Answer 6

Aggregated lympoid nodules in GALT.

Question 7

Lymphocyte homing:

Answer 7

Lymphocytes can return to the mucosa from which they came.

Question 8

Lymphocytes express integrin that binds blood vessel epithelium:

Answer 8

apha4beta7 : MACAM1

Question 9

Lymphocytes express ____ which responds to ____ secreted by gut epithelium.

Answer 9

CCR9 : CCL25

Question 10

Lymphocytes which enter the epithelium express:

Answer 10

aphaEbeta7 : E-cadherin (on epithelial cells).

Question 11

Functions of secreted IgA:

Answer 11

• Export toxins and pathogens from lamina propria.
• Bind and neutralize antigens internalized in endosomes.
• Bind and neutralize pathogens and toxins on gut surface.

Question 12

Tregs in gut:

Answer 12

Prevent inappropriate T cell responses to commensal bacteria.
- Secrete IL-10.