13-1: 1/31 - Immunology Of The Gi Tract

Front 1

Trefoil peptides:
Function

Back 1

Aid in defense and repair of gut epithelium via protective responses, inhibition of apoptosis, stimulation of EGF-receptors

Front 2

Paneth Cells:
Location
Secretions

Back 2

Located at base of crypt in small bowel

Secrete defensins--bactericidal activity

Front 3

Cholera:
Mode of infection

Back 3

Disassembles tight junctions between epithelial cells

Front 4

Gliadin:
Mode of initiating immune response

Back 4

Disassembles tight jns between epithelial cells to cause immune response

Front 5

What are the components of sub-epithelial innate immunity?

Back 5

Dendritic Cells
Intestinal macs
NKCs

Front 6

Where do intestinal macrophages reside?

Back 6

Peyer's patches

Front 7

Main component of gut adaptive immunity.

Back 7

Gut Associated Lymph Tissue (GALT)

Note: GALT is ANATOMICALLY-defined

Front 8

What are the four components of GALT?

Back 8

***********!!!!
Lymphatic tissue--appendix, Peyer's patches, tonsils
Lamina propria
Intraepithelial lymphocytes
Mesenteric LNs

Front 9

What comprises gut lymphatic tissue?
How do they differ from the rest of the gut?

Back 9

M Cells & Peyer's Patches: small intestine, mostly ileum; epithelium covering dome of patches unique! Instead of villi and crypts, they contain M CELLS (M = microfold)

Front 10

How to Peyer's Patches work? Begin with antigen.

Back 10

Antigen enters patch via M cells and allows lymphocytes to stimulate Ig production.

Patches have T cells, B cells, and APCs (macs and DCs)

Front 11

Lamina Propria:
Contents

Back 11

T cells, B cells, Macs, NKCs, ephils (rare), mast cells

Front 12

MadCAM-1:
Function

Back 12

ligand for integrin released by lamina propria CD4+ cells; expressed in mucosa and restricts migration of lymph cells to this site

Front 13

Elevated _______ in the lamina propria is rare. May indicate ________.

Back 13

Elevated ephils in lamina propria rare

May indicate helminthic dz

Front 14

Intraepithelial lymphocytes:
Location
Function
Relevance in disease

Back 14

Lymphocytes between intraepithelial cells

Have suppressor and stimulatory activity (re: immune system)

Help maintain tight jns

In celiac dz, there's an inc number of these cells***

Front 15

LN that serves GI tract.

Back 15

Mesenteric LNs

Front 16

What is the main antibody of the digestive tract?
Where else is it made?
Function?

Back 16

Secretory IgA:
Main ab of digestive tract
Made in mucosal secretions
Blocks bacterial adherence to mucosa (prevents colonization)

MAde in lamina propria

Poly-Ig receptor binds secretory IgA-->endocytosis-->cleaved once released into lumen where it exerts its properties

IgA also found in bile, saliva

Front 17

Beginning with antigen in M cell, describe the steps necessary to produce an immune response in the intestines.

Back 17

Ag in M cells brought to DC

T cell migration from Peyer's Patch-->Mesenteric LNs

DC's can also branch into lumen and activate naive T cells directly.

Produce more lymphocytes-->transport back to lamina propria

In LP, plasma cells produce IgA which is secreted into lumen

Front 18

Role of poly-Ig receptor.

Back 18

Poly-Ig receptor binds secretory IgA-->endocytosis-->cleaved once released into lumen where it exerts its properties

IgA also found in bile, saliva

Front 19

Administration of a soluble protein antigen orally has what effects when the antigen is delivered parentally?

Back 19

Admin of Ag orally prevents or markedly diminishes inflammatory response when Ag is given parentally

i.e., DEVELOP TOLERANCE

Front 20

T-regulatory cells:
Role
Secretions

Back 20

Produce IL-10, IGF-beta to suppress immune response

Front 21

What cells are important for tolerance?

Back 21

T regulatory cells (T-reg)
CD8+ suppressor cells
Intraepithelial lymphocytes
Myeloid derived suppressor cells

Front 22

Effect of aging on gut immune function.

Back 22

Overall, there is no data to suggest that gut immune fn is impaired w/aging

However:
With age there is dec'd gastric acid production
Number of Peyer's patches decrease

Front 23

Why should patients with Celiac disease abstain from rye and barley?

Back 23

Rye and barley products are often processed on machinery that handles wheat gluten!

Front 24

Celiac Disease:
Histologic features

Back 24

Atrophy of villi
Crypt hyperplasia
INC'd intraepithelail lymphocytes

THIS MUST BE DX'd BY HISTOLOGY

elimination of gluten-->clinical and histological improvement :) :) :)

Front 25

Celiac Disease:
Molecular pathophys
What ab's are produced?

Back 25

Gluten broken down into gliadin

Disrupts tight jns b/t epithelial cells

Tissue transglutaminase cross-links gliadin, which then binds APCs with HLA DQ2/8

Activates B/T cells

Produce Abs against gliadin, endomysial and tissue transglutaminase

Front 26

IgA tTG:
Test
Associated Disorder

Back 26

Blood test for ab against tissue transglutaminase

If positive, likely Celiac's, but need small intestine bx to be sure.

Front 27

Celiac Disease is associated with what other disorders?

Back 27

Down's
Turner's
DM

Front 28

Dematitis herpetiformis:
Pathophys
Associated Disorder

Back 28

Pruritic papular vesicular lzns resulting from deposition of anti-tissue transglutaminase Ab's (commonly on elbows)

SEEN IN CELIAC

Front 29

Celiac Disease:
Risks

Back 29

NHL
Small bowel lymphoma
Esophageal squamous cell cancer

Even if pt is asyx while eating gluten

Front 30

Back 30

Dermatitis herpetiformis

Celiac Dz