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45 Cards in this Set
- Front
- Back
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What is the immune reactant for Type I HS?
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IgE (123-EGG)
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What is the immune reactant for Type II HS?
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IgG (123-EGG)
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What is the immune reactant for Type III HS?
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IgG (123-EGG)
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What is the immune reactant for Type IV HS?
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TH1, TH2, CTL
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What is the Ag in Type I HS?
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soluble Ag
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What is the Ag in Type II HS?
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Cell- or matrix-associated Ag;
Cell-surface receptor |
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What is the Ag in Type III HS?
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Soluble Ag
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What is the Ag in Type IV HS?
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Soluble Ag (TH1 + TH2);
Cell-associated Ag (CTL) |
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What are the HS types that recognize soluble Ag?
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Types I, III, and IV (TH1 + TH2)
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What is the effector mechanism of Type I HS?
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mast cell activation
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What is the effector mechanism of Type II HS?
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Complement, FcR, and cells (phagocytes + NK cells)
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What is the effector mechanism of Type III HS?
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Complement, phagocytes
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What is the effector mechanism of Type IV HS?
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Macrophage activation (TH1)
Eosinophil activation (TH2) Cytotoxicity (CTL) |
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What is an example of a Type I HS rxn?
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systemic anaphylaxis
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What is an example of a Type II HS rxn?
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penicillin allergy (cell- or matrix-associated Ag)
Chronic urticaria (Ab against FCeR1a) (Cell surface receptor) |
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What is an example of a Type III HS rxn?
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serum sickness
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What is an example of a Type IV HS rxn?
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contact dermatitis, tuberculin rxn (TH1)
chronic asthma (TH2) contact dermatitis (CTL) |
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How rapid is the onset of Type I rxns?
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occur w/in minutes of exposure to Ag
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What is happening in Type I rxns?
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Ags combine w/ IgE Abs bound to mast cells via FcR, causing mast cells to degranulate and release mediators (eg histamine)
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What are the mediators associated with Type I response?
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Histamine
Prostaglandins Leukotrienes |
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What effects does histamine cause?
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Histamine dilates and increases the permeability of blood vessels (edema, redness), increase mucus production (runny nose), cause smooth muscle contraction (bronchi)
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What effects do prostaglandins cause?
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Prostaglandins cause contraction of smooth muscle of respiratory system and increased mucus secretion.
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What effects do leukotrienes cause?
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Leukotrienes cause bronchial spasms.
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What is an example of an enzyme released by mast cells upon activation?
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tryptase
chymase cathepsin G carboxypeptidase |
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What is an example of a toxic mediator released by mast cells upon activation?
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histamine
heparin |
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What is an example of a cytokine released by mast cells upon activation?
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IL-3, IL-4, IL-5, IL-13, GM-CSF, TNF-alpha
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What is an example of a chemokine released by mast cells upon activation?
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CCL3
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What is an example of a lipid mediator released by mast cells upon activation?
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Prostaglandins D2, E2
Leukotrienes B4, C4 PAF |
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What are the biological effects of the enzymes tryptase, chymase, cathepsin G, and carboxypeptidase released from mast cells upon activation?
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These enzymes remodel tissue matrix
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What are the biological effects of the toxic mediators histamine and heparin released from mast cells upon activation?
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Toxic to parasites
Increase vascular permeability Vasoconstriction Bronchoconstriction |
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What are the biological effects of the cytokines IL-4 and IL-13 released from mast cells upon activation?
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IL-4 and IL-13 stimulate and amplify TH2 cell response
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What are the biological effects of the cytokines IL-3, IL-5, and GM-CSF released from mast cells upon activation?
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IL-3, IL-5, and GM-CSF promote eosinophil production and activation
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What are the biological effects of the cytokine TNF-alpha released from mast cells upon activation?
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TNF-alpha promotes inflammation, stimulates cytokine production by many cell types, and activates endothelium
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What are the biological effects of the chemokine CCL3 released from mast cells upon activation?
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CCL3 attracts monocytes, macrophages, and neutrophils
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What are the biological effects of the lipid mediators prostaglandins and leukotrienes released from mast cells upon activation?
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Prostaglandins and leukotrienes cause smooth muscle contraction, increase vascular permeability,, and stimulate mucus secretion
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What are the biological effects of the lipid mediator PAF released from mast cells upon activation?
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PAF attracts leukocytes, amplifies production of lipid mediators,and activates neutrophils, eosinophils, and platelets
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Mast cell activation and granule release affects... (3)
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GI tract
Airways Blood vessels |
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Mast cell activation/granule release effect on blood vessels...
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↑ blood flow
↑permeability |
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Mast cell activation/granule release effect on airways...
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↓ diameter
↑ mucus secretion |
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What are some common food allergens responsible for IgE-mediated allergic rxns?
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tree nuts
peanuts shellfish milk eggs fish |
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What are possible responses to common food allergens that elicit IgE-mediated allergic rxns?
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vomiting
diarrhea pruritis (itching) urticaria (hives) anaphylaxis (rarely) |
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Allergens are often introduced via the mucosa at low dose, which favors IgE production. What are some characteristics of such allergens?
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relatively small
highly soluble carried on desiccated particles (pollen grains, mite feces) |
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What is Der p 1?
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Der p 1 is a protease from the mite
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What is occludin?
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Occludin is a protein that maintains tight junctions
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Give an overview of allergy to the house dust mite
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1. Tight junctions seal the barrier of airway epithelium.
2. The enzyme Der p1 cleaves occludin in tight junction. 3. Der p 1 taken up by dendritic cells for Ag presentation and TH2 priming. 4. Der p 1-sp IgE binds to mast cells; Der p 1 triggers mast cell degranulation. |
