4. Gut Immunology Flashcards

1
Q

What is the largest immune organ in the body that consists of multi-follicular Peyer’s Patches and Isolated Lymphoid Tissue (ILT)

A

Gut-Associated Lymphoid Tissue (GALT)

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2
Q

What are defensins

A

Diverse antimicrobial peptides (AMPs) contributing to the antimicrobial action and mucosal host defense in the GI

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3
Q

What immunoglobulin is key for maintaining a Peaceful Bacteria-Host interaction

A

Secretory IgA

  • does not activate complement
  • does not activate phagocytes
  • resistant to proteolysis
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4
Q

What is Dysbiosis

A

Bad relationship between gut microflora leading to DYSREGULATION of the immune system and inflammation

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5
Q

What do Short-chain fatty acids do for our immune system

A

Promotre Treg differentiation and secretory IgA production and stimulate production of mucus

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6
Q

What is food allergy and celiac disease

A

Failure to induce tolerance to food proteins

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7
Q

Why is peripheral tolerance needed for GI

A

Intestinal antigens are not available in the thymus so Central Tolerance does not prevent responses against intestinal antigens such as food and commensal organisms

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8
Q

What CD is required for oral tolerance

A

CD25+

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9
Q

The most common forms of immune-mediated adverse reactions to food (Type 1 hypersensitivity) are characterized by

A

Development of IgE against the food allergens

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10
Q

What types of hypersensitivity are associated with food allergies

A

Type 1- IgE mediated

Types 3 and 4- Non IgE mediated

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11
Q

Describe the primary allergen encounter

A
  • Ingested allergen elicits an adaptive immune response
  • B cells mature into plasma cells to make IgE to allergen
  • IgE enters circulation and is bound by FcRE (CD23)** on mast cells in the tissues
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12
Q

Describe the secondary allergen encounter

A

Cross-linking of allergen causes mast cell degranulation that releases vasoactive amines, cytokines/chemokines and lipids

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13
Q

Why do GI allergens (food) cause allergic responses in skin

A

After primary encounter allergen fragments are internalized from the distributed throughout the body

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14
Q

What are some mediators of Mast Cells

A
Histamine
TNF-a and IL-1
Prostaglandins
IL-5
Leukotrienes
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15
Q

What cells are central for both local and systemic manifestations of food allergy

A

Mast cells

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16
Q

GI manifestations of food allergy are dependent on what ILs

A

IL-4
IL-13
IL-9

17
Q

How do Treg cells control food allergy

A

Treg cell derived IL-10 and TGF-B suppress Th2 immunity and INHIBIT MAST CELL reactivity, REDUCE IgE synthesis and may increase IgG and IgA synthesis

18
Q

What supplements suppress inflammation

A

Vitamin D, A and folate

19
Q

How does the GUT MICROBIOTA suppress allergic immune responses

A

Induction of Treg cells and or direct suppresion of Basophils and MAST CELLS

20
Q

Skin prick allergen testing using what type of hypersensitivity

21
Q

How do peanuts and other nuts contribute to shock

A

Production of C3a

22
Q

What plays the central role in food-induced anaphylaxis

A

Mast cells activated by IgE cross-linking of FceRI

23
Q

What allergens are associated with wheat

A

Alpha-amylase inhibitors
Agglutinin
Peroxidase

24
Q

What is Food-Dependent Exercise-Induced Anaphylaxis (FDEIA)

A

Exercise or aspirin enhance absorption of undigested immuno-reactive allergens into circulation

25
What is an example of Non-IgE mediated food allergy
Cow's milk allergy where symptoms don't show for over 48 hours is NOT lactose intolerance Breastfeeding mother should remove milk from diet also
26
What are the genetics behind Celiac Disease
HLA-DQ2 and DQ8 play a role in orchestrating adaptive immune response against gluten peptides TG2 are associated with the disease (tissue transglutaminase 2)
27
CD patients express what HLA
HLADQ2.5
28
What type of hypersensitivity is associated with CD
Type 4