03c: GI Immunology Flashcards

1
Q

GI tract immune system faces specific challenges, namely from (X) pathogens.

A

X = food antigens and commensal bacterial (part of gut)

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2
Q

List general immunological structures in GI tract that battle pathogens.

A
  1. Tonsils
  2. Peyer’s patches
  3. Lamina propria follicles
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3
Q

T/F: GI tract immunity particularly emphasizes tight regulation, though other innate and adaptive responses present.

A

True

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4
Q

T/F: Humoral immunity plays little to no role in GI defenses.

A

False - major role in local defense

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5
Q

GI Immunity: List the two components of the epithelial barrier.

A

Tight junctions and mucus

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6
Q

List the specialized epithelial cells with immune function in GI tract.

A
  1. Adsorptive epithelial cells
  2. M cells
  3. Paneth cells
  4. Goblet cells
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7
Q

GI innate Immunity: Goblet cells important for (X) and adsorptive epithelial cells for (Y).

A
X = secreting mucus
Y = secreting cytokines
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8
Q

GI innate Immunity: M cells important for (X) and paneth cells for (Y).

A
X = antigen sampling/presentation
Y = secreting anti-bac peptides
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9
Q

T/F: Mucus is both a chemical and physical barrier in GI immune system.

A

True

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10
Q

Mucus: (hydrated/dehydrated) gel, made up of proteins that have been extensively modified via (X).

A

Hydrated

X = glycosylation

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11
Q

GI Immunity: Some (X) from (Y) cells stimulate mucus production in GI tract.

A
X = cytokines
Y = epithelial
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12
Q

Immune system: (X) ligands, such as LPS, bind (Y) receptors. This leads to signaling events that stimulate which responses?

A
X = PAMPs
Y = toll-like (TLRs)

Cytokines, adhesion, inflammation, adaptive immunity

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13
Q

T/F: Mucus contains neutrophils.

A

True

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14
Q

T/F: TLRs in GI tract are clustered together and localized to specific regions.

A

False - widely distributed

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15
Q

TLR signaling in GI tract often leads to which responses?

A

Increased epithelial motility, proliferation, and tight junctions (NOT inflammation)

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16
Q

There’s a (lower/higher) threshold for TLR activation in GI tract. Thus, (less/more) (X) needed to activate receptor.

A

Higher; more

X = PAMPs

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17
Q

Which TLR would you expect to find on luminal surface of GI tract? And on basolateral surface? What does each bind?

A

Luminal: TLR-4 (LPS on gram-neg bac)

Basolateral: TLR-5 (flagellin on invaded bacteria)

18
Q

The (basal/luminal) surface of GI epithelium is considered “anti-inflammatory” environment, due to cell secretion of (X).

A

Basal;

X = IL-10 and TGF-beta

19
Q

List the cells in GI tract that secrete anti-inflamm agents, specifically (X).

A

X = IL-10 and TGF-beta

DCs, macrophages, epithelial cells

20
Q

T/F: Unlike other parts of immune system, GI tract has “anti-inflamm” DCs and macrophages that aren’t involved in antigen processing/killing.

A

False - they retain that function

21
Q

GI Immunity: lymphocytes are (localized/scattered) throughout (mucosa/submucosa/muscularis) layer.

A

Scattered; submucosa

22
Q

T/F: The major form of adaptive immunity in gut is humoral immunity.

A

True

23
Q

Major form of cell-mediated immunity in GI tract comes from (X) cells.

A

X = Th17 and Tregs

24
Q

GI Immunity: (X) cells are in contact with (basal/lateral/luminal) surface of epithelium. They act as shuttle/uber, dumping pathogen to (Y) cell.

A

X = M
Lateral (sandwiched between epithelial cells)
Y = DC

25
Q

GI Immunity: following DC uptake, maturation, and Ag processing, MHC presentation occurs in (X).

A

X = mesenteric lymph nodes OR Peyer’s patches (follices/parafollicular zones)

26
Q

GI Immunity: (X) species of pathogens are especially good at hijacking the (Y) cell shuttle system, thus getting past epithelial barrier no problem.

A
X = Salmonella
Y = M
27
Q

GI Immunity: (X) cells convert vitamin (Y) to (Z). This acts as a “homing signal” for which immune system cells?

A
X = DCs
Y = A
Z = retinoic acid

lymphocytes

28
Q

GI Immunity: retinoic acid allows lymphocytes to home back to GI due to its (up/down)-regulation of (X).

A

Up-regulation;

X = CCR9 and integrin (alpha-4-beta-7)

29
Q

GI Immunity: When lymphocytes home back to GI, which specific tissue layer are they returning to from circulation?

A

Lamina propria

30
Q

The dominant protective cell-mediated immune response consists of (X) cells. Which of their actions is most prominent in GI?

A

X = Th17

Secretion of IL-22 (increases epithelial barrier integrity)

31
Q

GI Immunity: plasma cell produces (mono/di/poly)-meric Ig(X). Of the (Y) g of Ig we make per day, how much of it is Ig(X)?

A

Dimeric;
X = A
Y = 3

2 of 3 g is IgA

32
Q

T/F: IgA Fc segment is pro-inflammatory.

A

False

33
Q

Invaded bacteria can actually be transported back across the epithelial cell. This is carried out by presence of (X) in (Y) tissue layer.

A
X = IgA
Y = lamina propria
34
Q

T/F: IgA levels in blood circulation are very low.

A

True

35
Q

T/F: IgG is the only other Ab secreted in nearly same quantities as IgA in gut lumen.

A

False - secreted into gut lumen, but in lower quantities than IgA

36
Q

GI immunity: A special receptor, (X), allows bi-directional transport of Ig(Y). Which cells express this receptor?

A

X = FcRn (neonatal Fc receptor)
Y = G
Intestinal epithelial cells

37
Q

Major form of humoral immunity in the gut:

A

IgA, IgG, IgM

38
Q

Crohn’s disease affects which part(s) of bowel? Which tissue layers?

A

Entire bowel thickness and all regions

39
Q

Ulcerative colitis affects which part(s) of bowel? Which tissue layers?

A

Colonic mucosa

40
Q

(X) disease: Unusual sensitivity to gluten proteins, manifesting as (Y) symptom in which region/tissue layers of bowel?

A
X = celiac 
Y = inflammation

Small bowel mucosa

41
Q

There’s an abnormal (X) T cell response in celiac disease.

A

X = CD8

42
Q

There’s an abnormal (X) T cell response in food allergy.

A

X = CD4 (Th2)