Flashcards in Ch7: Hypersensitivity and Autoimmunity Deck (129)
What are allergens?
Things that the immune system develops an over-active response to
What are 4 common sources of allergens?
1. inhaled materials
2. injected materials
3. ingested material
4. contacted materials
How many types of hypersensitivity are there?
Name of each hypersensitivity reaction?
1. Type I: Immediate Hypersensitivity
2. Type II: Antibody-mediated diseases
3. Type III: Immune complex mediated diseases
4. Type IV: T cell mediated diseases
What are the steps of Type I Hypersensitivity's sensitization?
1. Allergens taken up by APC's
2. Proteins degraded
3. Peptides presented as peptide:MHC to specific T cells
4. Th2 cells then produce cytokines to isotype switch to IgE
5. IgE binds to Fc-epsilon-RI receptors on Mast cells
6. Repeat exposure of allergen causes activation of mast cell and release of mediators
Two kinds of mediators that mast cells release?
1. Vasoactive amines and lipid mediators immediately after repeat exposure
2. Cytokines released hours later
Does IgE need antigen to bind and coat mast cells?
Basophils and mast cells are very similar but differ in what terms?
Mast cells: tissues
5 main classes of products released by mast cells and which are prestored?
1. enzymes (prestored)
2. toxic mediators (prestored)
3. cytokines (TNF-alpha only prestored)
5. lipid mediators
Effect of enzymes released by mast cells?
Remodeling of CT matrix
Two main toxic mediators released by mast cells?
Histamine and heparin
Function of histamine and heparin release?
1. Toxic to parasites
2. leaky vessels
3. Smooth muscle contraction
Function of mast cell TNF alpha? 3
1. promotes inflammation
2. stimulates cytokine production
3. activates endothelium
Function of IL4 and IL13 release
Stimulate and amplify TH2 cell response
Function of IL3, IL5, and GM-CSF release?
Promote eosinophil production and activation
Function of CCL-13 release of mast cells?
Chemotactic for phagocytes
Function of leukotriene release of mast cells?
1. Smooth muscle contractin
2. Increase vessel leakiness
3. Cause mucus secretion
Function of platelet activating factor
1. Chemotactic for leukocytes
2. Amplifies production of lipid mediators
3. Activates neutrophils, eosinophils, and platelets
Function of prostaglandins?
Function of vasoactive amines?
Smooth muscle contraction
IMmediate Phase Type I hypersensitivity involves what cells?
Late phase Type I hypersensitivity involves what cells?
What causes the wheal and flare of a Type I reaction?
Mast cell degranulation
Late-phase reaction occurs 6-8 hours later because of what?
Leukotrienes, chemokines, cytokines synthesized by mast cells
Degranulation in GI tract of Type I causes what?2
Diarrhea and vomiting
Degranulation in Airways causes what? 2
Phlegm and coughing
Degranulation in blood vessels causes what? 3
Increased lymph flow
Treatment for Type I involves what?
Block effects of inflammatory mediators (histamine and leukotrienes)
Can't stop the cause: IgE crosslinking
When allergen is in skin, what results? (2)