Cutaneous and Mucosal Immune Systems

Question 1

Waldeyer’s ring made of…

Answer 1

Adenoids

Palatine tonsil

Lingual tonsil

Question 2

Examples of GALT

Answer 2

Peyers patch (with M cells)

Isolated lymphoid follicles

Question 3

Gut lymphoid follicle appearance

Answer 3

Big follicle with GC

T cell areas fan out toward the sides

Dome separates GC from the epithelium (M cells)

Question 4

What do M cells do?

What does this result in?

Answer 4

Capture bacteria in the gut lumen

deliver bacteria/antigens to dendritic cells and lymphocytes in PP’s

**This activates B/T/DC’s (specific effector T cells and plasma cells that produce specific AB’s

Question 5

IgA transcytosis across intestinal epithelial cells starts via binding to the _____

Answer 5

Polymeric IgA receptor (pIgR)

(binds as a dimer)

Question 6

What cells extend a process across the epithelial layer?

Why would it do such a thing?

Answer 6

Dendritic cell

It does this to capture/sample antigen from the gut lumen to activate the cell

Question 7

T cell localization in intestinal endothelium (3 steps)

Answer 7

1. GUt homing effetor T cells bind to intestinal vascular endothelium
2. Enter Lamina Propria
3. Once in LP, the T cells bind to chemokines being expressed by the intestinal epithelium

Question 8

____ is homing signal for LN (elsewhere in body)

_____ is the homing signal that specifically targets gut epithelium

Answer 8

CCR7 elsewhere

CCR9 recognizes chemokine receptor in gut

Question 9

Naive lymphoctes in Peyer’s patch give rise to ______ that travel in the lymph and blood to gain acces to the ______ of the mucosal tissue

Answer 9

Effector cells

Lamina propria

Question 10

IgG is transported from the

blood –> Lamina propria –> gut lumen

by binding to ____

..which is subsequently _____

Answer 10

FcRn receptor

recycled

Question 11

Anatomical features of mucosal immune system (3)

Answer 11

1. Intimate interactions between mucosal epithelial and lymphoid tissues
2. Discrete compartments of diffuse lymphoid tissue and more organized structures such as Peyer’s patches, isolated lymphoid follicles, and tonsils
3. Specialized antigen uptake by M cells in the Peyer’s patches, adenoids, and tonsils

Question 12

Effector mechanisms of mucosal immune system (2)

Answer 12

1. Activated effector T cells predominate even in the absence of infection (sometimes these are commensal bacteria and if they end up invading, there is a mechanism to protect against this)
2. Plasma cells are in the tissues where antibodies are needed (IgA)

Question 13

Immunoregulatory environment of mucosal immune system (2)

Answer 13

1. Dominant and active downregulation of inflammatory immune response to food and other innoculous environmental antigens
2. Inhibitory MQ and tolerance-inducing DC