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28 Cards in this Set
- Front
- Back
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Types of Hypersensitivities and description
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Type I, II, III, IV
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What is a Hypersensitivity
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immune response to innocuous or self antigens
autoimmune is subset of hypersensitivity |
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What is atopy?
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propensity to have an allergic response
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What is Type I hypersensitivity
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Immediate IgE antibody; triggers mast cells and eosinophils. effector function determined by Fc receptors
Typical Allergic response |
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What is Type II Hypersensitvity
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AB mediated; IgG reacts with surface or matrix Ag
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What is Type III Hypersensitivity
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Immune complex mediated; Ag-Ab complexes
Ag-Ab get stuck somewhere |
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What is Type IV Hypersensitivity
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T cell mediated
poison ivy |
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What determines type of Hypersensitivity
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Effector mechanism NOT SYMPTOMS
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Type I hypersensitivity requires what?
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Isotype switching
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Whats determines Effector function?
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Opsonization by Fc Receptor
complement activation ADCC by Fc receptor on NK cells Transcytosis which also allows passive immunization of fetus via breat milk Activate mast cells and IgE |
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What does IgE bind and what happens
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FcEpsilon. Once IgE binds it is irreversible and very little free IgG
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Is IgE constitutive or induced on mast cells? Eosinophils?
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Constitutive
Induced |
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What does IgE usually do?
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Cause increased contractility of smooth muscle to expel parasites
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Why do kids get more allergies now.
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The wimps and don't eat enough dirt to get parasites
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Which Hypersensitivities do mast cells contribute too
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Type I and III.
Mast cells also found in species lacking adaptive system(Ab like IgE) |
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What is sensitization phase of allergy development
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Sensitization:CD4 TH2 T cell cytokines cause isotype switching to IgE
CD40L and IL4 from TH2-->Activation Induced Deamidase in B cell(DNA repair enzyme required for IgE switching |
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What is effector phase of allergy development
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IgE triggers Mast Cell Degranulation
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What causes Immediate actions? Late actions
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Granules
Lipid Effectors and Cytokines |
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What is main goal of treatment?
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Increase T1:T2 ratio
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What does Mast Cell Protease do?
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act on fibrinogen(reduce clotting)-->macrophage to release chemokines; some create molecules to attract neutophils; cause T cells to secrete IL13-->mucus production
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How is Mast cell protease helpful?
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protects against snake venom, break down toxins, mice w/o mast cell 10x more sensitive to viper venom
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Leukotrienes and cytokines
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late phase response of allergy w/ influx of T cells, eosinophils, more tissue destruction and remodeling
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What induces eosinophils to have Fc?
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immune response
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What type of response can ingested Ag cause?
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food allergy
local or systemic responses(Ag absorbed and spread in blood) |
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How do you treat anaphylaxis?
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adrenaline(Epipen)
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What is anaphylaxis?
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systemic response of IgE x-linking receptors on mast cells and basophils
Systemic Ag |
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What does anaphylaxis cause?
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Laryngeal Edema, Bronchoconstriction, hypotension, vascualr leakage
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PAF and anaphylaxis
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PAF serum levels controlled by PAH acetyl hydrolase
PAF receptors on platelets, monos, macros, neutros PAF knockout mice show less anaphylaxis failure of PAF acetylhydrolase to clear PAF may cause anaphylaxis |
