4. Gut Immunology Flashcards
What is the largest immune organ in the body that consists of multi-follicular Peyer’s Patches and Isolated Lymphoid Tissue (ILT)
Gut-Associated Lymphoid Tissue (GALT)
What are defensins
Diverse antimicrobial peptides (AMPs) contributing to the antimicrobial action and mucosal host defense in the GI
What immunoglobulin is key for maintaining a Peaceful Bacteria-Host interaction
Secretory IgA
- does not activate complement
- does not activate phagocytes
- resistant to proteolysis
What is Dysbiosis
Bad relationship between gut microflora leading to DYSREGULATION of the immune system and inflammation
What do Short-chain fatty acids do for our immune system
Promotre Treg differentiation and secretory IgA production and stimulate production of mucus
What is food allergy and celiac disease
Failure to induce tolerance to food proteins
Why is peripheral tolerance needed for GI
Intestinal antigens are not available in the thymus so Central Tolerance does not prevent responses against intestinal antigens such as food and commensal organisms
What CD is required for oral tolerance
CD25+
The most common forms of immune-mediated adverse reactions to food (Type 1 hypersensitivity) are characterized by
Development of IgE against the food allergens
What types of hypersensitivity are associated with food allergies
Type 1- IgE mediated
Types 3 and 4- Non IgE mediated
Describe the primary allergen encounter
- 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
Describe the secondary allergen encounter
Cross-linking of allergen causes mast cell degranulation that releases vasoactive amines, cytokines/chemokines and lipids
Why do GI allergens (food) cause allergic responses in skin
After primary encounter allergen fragments are internalized from the distributed throughout the body
What are some mediators of Mast Cells
Histamine TNF-a and IL-1 Prostaglandins IL-5 Leukotrienes
What cells are central for both local and systemic manifestations of food allergy
Mast cells
GI manifestations of food allergy are dependent on what ILs
IL-4
IL-13
IL-9
How do Treg cells control food allergy
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
What supplements suppress inflammation
Vitamin D, A and folate
How does the GUT MICROBIOTA suppress allergic immune responses
Induction of Treg cells and or direct suppresion of Basophils and MAST CELLS
Skin prick allergen testing using what type of hypersensitivity
Type 1
How do peanuts and other nuts contribute to shock
Production of C3a
What plays the central role in food-induced anaphylaxis
Mast cells activated by IgE cross-linking of FceRI
What allergens are associated with wheat
Alpha-amylase inhibitors
Agglutinin
Peroxidase
What is Food-Dependent Exercise-Induced Anaphylaxis (FDEIA)
Exercise or aspirin enhance absorption of undigested immuno-reactive allergens into circulation
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
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)
CD patients express what HLA
HLADQ2.5
What type of hypersensitivity is associated with CD
Type 4
