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58 Cards in this Set
- Front
- Back
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define "Hypersensitivity" or "Allergy"
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an "overt" reaction to an otherwise "innocuous" antigen
ie. an "allergen" |
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Hypersensitivity Types I-III are all ______-mediated and are distinguised from each other by _________ and ________
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*antibody-mediated
*by "the types of antigens recognized" *and "the classes of Ab involved" |
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How is each type (Type I, II, III, and IV) of hypersensitivity mediated?
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Type I: IgE
Type II: IgG Type III: IgG Type IV: T-H1, T-H2, and Tc cells |
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Type I responds to what type of antigen?
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soluble antigen
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Type II responds to what type of antigens?
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cell-associated antigen
matrix-associated antigen cell-surface receptors |
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Type III responds to what type of antigen?
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soluble antigen
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T-H1 and T-H2 mediated Type IV reactions respond to what type of antigen?
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soluble antigen
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Tc-cell mediated Type IV reactions respond to what type of antigen?
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cell-associated antigen
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What is the effector mechanism for Type I reactions?
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mast-cell activation
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What is the effector mechanism for Type II reactions involving cell- or matrix- associated antigen?
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complement
FcR+ cells |
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what are two types of FcR+ cells?
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1. phagocytes
2. NK cells |
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What is the effector mechanism for Type II reactions involving cell-surface receptors?
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Ab alters signaling
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What is the effector mechanism for Type III reactions?
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complement
phagocytes |
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What are the 2 effector mechanisms for Type IV reactions involving soluble antigen?
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1. macrophage activation
2. IgE production |
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What is the effector mechanism for Type IV reactions involving cell-associated antigen?
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cytotoxicity
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3 common Type I reactions are:
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1. allergic rhinitis
2. asthma 3. systemic anaphylaxis |
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"drug allergies" are often Type-____ reactions, that are _____-mediated, involving _______ or _______ antigen.
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Drug Allergies:
*Type-II *IgG-mediated *cell-associated antigen *matrix-associated antigen |
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a common example of a Type-II reaction involving cell-surface receptors is:
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chronic urticaria
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2 common Type-III reactions are:
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1. serum sickness
2. arthus reaction |
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2 common Type IV, T-H1 mediated reactions:
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1. contact dermatitis
2. tuberculosis |
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2 common Type IV, T-H2 mediated reactions:
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1. chronic asthma
2. allergic rhinitis |
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the main Type IV, Tc-cell mediated reaction is:
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graft rejection
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Inhaled allergens have what features?
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*proteins
*enzymatically active *low dose req'd *low molecular weight *soluble *stable *bind MHC-II |
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Inhaled allergens promote:
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priming of T-H2 cells that drive IgE
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What is "Der p 1" and why is it unique?
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"Der p 1" is an enzyme in the fecal pellet allergen from dust mites.
It is unique because it cleaves tight junctions of airway epithelium |
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naive CD4 T-cells develop into T-H2 cells when stimulated by:
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IL-4, -5, -9, -13
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naive CD4 T-cells develop into T-H1 cells when stimulated by:
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IFN-γ and IL-12
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5 important IgE-mediated reactions:
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1. anaphylaxis
2. wheal-and-flare 3. Hay fever - rhinoconjunctivitis 4. asthma 5. food allergy |
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The "Big 8" food allergies are:
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peanuts
tree nuts fish shellfish milk eggs wheat soy |
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"oral allergy syndrome" is what type of food allergy?
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type 2
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the two categories of food allergies are:
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type-1 and type-2
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this food allergy type is less resistant to digestion and less severe
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type 2
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what is "atopy"
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atopy is the tendency to mount IgE-mediated reactions to a wide variety of allergens
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what is serum sickness?
what type of reaction is it? |
a reaction to proteins from a non-human animal source.
Type-III |
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what is the "hygiene hypothesis"
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exposure to microorganisms shift the T-H1/T-H2 balance towards T-H1
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____ is secreted by _____ cells, ____ cells, and _____ to stimulate B-cells to switch to IgE production
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IL-4
T-H2 cells, mast-cells, basophils |
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Where can the FceR receptor be found?
why is the FceR receptor important? |
*present on fixed mast-cells, circulating basophils, and activated eosinophils
*it binds IgE. When the bound IgE is cross-linked by allergen, it stimulates the mast-cell or basophil to secrete IL-4 |
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what is the function of IL-4 secreted from mast-cells
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stimulate/amplify T-H2 cell response
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what cells line the body surfaces where allergens are likely to enter?
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mast cells
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what is the major difference between IFN-γ and IL-4
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IFN-γ: secreted by T-H1 cells, inhibits T-H2 growth
IL-4: secreted by T-H2, promotes T-H2 growth |
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what is "histamine"?
what cell releases it? |
a vaso-active amine that causes increased blood flow and vessel permeability
released by activated mast-cells |
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when a mast-cell is activated by an allergen, it "degranulates", releasing what 5 types of mediator molecules
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1. enzymes
2. toxic mediator 3. cytokines 4. chemokines 5. lipid mediator |
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name 2 "lipid mediators" released from mast-cells
what is their function? |
prostaglandins
leukotrienes both responsible for: *smooth muscle contraction *vascular permeability |
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what "cytokines" are released from mast-cells after they are activated? What do they do?
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IL-4: amplify T-H2 response
IL-3: eosinophil production TNF-α: promotes inflammation and cytokine release by other cells |
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what is the time difference between an "immediate" and "late-phase" reaction?
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immediate: within seconds
late-phase: 8-12 hours |
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what chemical mediator is responsible for an "immediate" reaction?
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histamine
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what chemical mediators are responsible for a "late-phase" reaction?
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prostaglandins, leukotrienes, chemokines, cytokines
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what is "major basic protein" and what is its function
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*toxic protein secreted by eosinophils
*toxic to parasites, triggers histamine release |
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what does a "wheal-and-flare" response look like?
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like a mosquito bite
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what does an "edematous" response look like?
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an area of swelling
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what allergic effects are displayed by:
airways GI tract blood vessels |
airways: increased mucus production, bronchial constriction
GI tract: vomiting, diarrhea blood vessels: system-wide histamine release --> anaphylaxis |
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allergen inhalation causes what 2 allergic conditions?
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rhinitis
asthma |
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what do "desensitization shots" do?
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reverse the T-H1/T-H2 balance
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what is "celiac disease"
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intestinal condition caused by immune response to "gluten"
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where is "gluten" found
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wheat
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what is an "arthus reaction"
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Type-III reaction, triggered in the skin, forms IgG immune complexes
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what is "farmers lung"
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a Type-III, IgG-mediated reaction from inhaled mold spores
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what are "delayed-type hypersensitivity" reactions?
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Type-IV reactions, mediated by T-H1 cells and CD8 cells
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