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60 Cards in this Set
- Front
- Back
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Name for Type I Hypersensitivity Reactions
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Immediate hypersensitivity
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Molecular mediators of Type I Hypersensitivity
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Th2, IgE, mast cell, eosinophils
mast-cell derived mediators and cytokine-mediated inflammation |
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Name for Type II Hypersensitivity Reactions
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Antibody-mediated Hypersensitivity
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Molecular mediators of Type II Hypersensitivity
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IgM, IgG against cell surface/ECM antigens
complement and FcR-mediated recruitment and activation of WBCs opsonization and phagocytosis of cells |
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Name for Type III Hypersensitivity Reactions
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Immune complex-mediated hypersensitivity
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Molecular mediators of Type III hypersensitivity
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IgM/IgG complexes aggregate
complement and FcR-mediated recruitment and activation of WBCs |
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Name for Type IV hypersensitivity
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T cell mediated hypersensitivity
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Molecular mediators of Type IV hypersensitivity
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CD4+ T cells --> DTH
CD8+ T cells --> cytotoxicity |
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What is an immune complex?
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A complex of Ab-Ag
where Ag are soluble antigens |
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When do Type I hypersensitivities occur?
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on encounter with foreign antigen to which the lymphocytes have been previously exposed
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Synonyms for Type I hypersensitivity
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allergy, atopy, immediate hypersensitivity
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Atopic patients are patients that...
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show a strong propensity to develop hypersensitivity reactions
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examples of Type I hypersensitivities
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hay fever
food allergies bronchial asthma anaphylaxis |
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What proportion of the population has allergies?
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20%
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Pathway to mast cell activation
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Ag --> IgE production --> IgE binds FcR of mast cell
cross-linking of bound IgE by antigen releases mast cell mediators |
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effects of mast cell mediators
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increase vascular permeability & smooth muscle contraction (w/in minutes)
cytokines recruit PMNs and eosinophils (w/in hours) |
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Primary cause of tissue injury from type I hypersensitivity
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late phase reaction = inflammation
mediated by cytokines |
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Compared to sensitized patients, non-sensitized patients do not...
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mount a strong Th2 response to most non-self antigens
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Sensitized patients' primary response to certain antigens, e.g.: pollen =
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Th2 development
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Th2 release ___ and ____, which stimulate B cells to produce _____
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Th2 release IL-4 & IL-13, which stimulate B cells to produce IgE
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T/F: atopicism has a strong genetic basis
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TRUE
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What precisely do IgE bind on mast cells?
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FcR specific for epsilon heavy chain
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process of coating mast cells with IgE specific for a certain Ag =
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SENSITIZATION
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In normal patients, mast cells carry IgEs specific for...
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many different antigens
none of which stimulate a strong enough response to get Type I HSR |
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Which cytokines stimulate B cells to produce IgE?
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IL-4
IL-13 |
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Mast cells are found in all _____ tissues
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Mast cells are found in all CONNECTIVE tissues
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Inhaled antigens activate mast cells where?
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in submucosal tissues of the bronchus
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Ingested antigens activate mast cells where?
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in intestinal wall
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Functions of chains in Fc-epsilon-RI
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3 chains
1 binds Fc 2 have signaling function |
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Fc-epsilon-RI stimulated by cross linking ---> (3 responses)
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DEGRANULATION
synthesis and secretion of LIPID MEDIATORS synthesis and secretion of CYTOKINES |
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Effects of histamines
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dilation of small vessels, increased vascular permeability, contraction of smooth muscle
proteases may damage local tissues arachnidonic acid metablites include PGs cytokines induce local inflammation |
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effects of prostaglandins
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vascular dilation
leukotrienes stimulate prolonged contraction |
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Principle WBCs involved in late phase reactions of Type I HSR
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eosinophils, PMNs, Th2
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cytokines that stimulate PMN and eosinophil mediated inflammation
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TNF and IL-4
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eosinophils and PMNs liberate _____
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proteases
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which cytokine activates eosinophils?
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IL-5
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which cytokine stimulates production of Th2 and mast cells in type I HSR?
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IL-5
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Th2 secretes IL-13 which stimulates ______
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secretion of mucus in epithelium of airway
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mast cells secrete _____, which stimulates secretionof mucus in the epithelium of airway
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histamine
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histamine release in gut -->
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increased peristalsis
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Aims of treatments for Type I HSR
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inhibit mast cell degranulation
oppose effects of mast cell mediators\ decrease inflammation |
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All asthma includes activation of ____, but only some involves the production of _____
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All asthma includes activation of mast cells, but only some involves the production of IgE
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Repeated administration of small doses of allergens =
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desensitization
treatment modality for Type I HSR |
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Where do immune complexes usually deposit?
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in vessels at sites of turbulence (i.e.: branches)
or at sites of high pressure (i.e.: kidney glomeruli) |
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Immune-complex HSR usually results in what type of disease?
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systemic
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3 examples of immune-complex mediated disease?
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vasculitis
arthritis nephritis |
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production of autoantibodies is the effect of ____
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failure of self-tolerance mechanisms
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examples of antibody-mediated diseases
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late sequelae of strept infections
post-stretp glomerulonephritis |
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late sequelaue of strept infections
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post infection production of anti-strept antibodies that cross react with heart muscle antigens
deposition of antibodies in heart --> RHEUMATIC FEVER |
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two infectious agents that increase risk for developing immuno complex disease
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EBV
malaria |
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Pathway for IgG1 & IgG3 - mediated tissue injury
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IgG1 & IgG3 bind FcR's on macrophages and PMN, activation, inflammation
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Pathway for IgG1, IgG3 and IgM mediated tissue injury
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classical system of complement -->
WBC recruitment and inflammation |
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autoimmune hemolytic anemia
- target antigen - mechanism of disease - clinical manifestation |
autoimmune hemolytic anemia
target antigen: RBC membrane proteins mechanism of disease: opsonization & phagocytosis of RBCs clinical manifestation: hemolysis, anemia |
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autoimmune TTP
- target antigen - mechanism of disease - clinical manifestation |
autoimmune TTP
target antigen: platelet membrane proteins mechanisms of disease: opsonization and phagocytosis of platelets clinical manifestation: bleeding |
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pemphigus vulgaris
- target antigen - mechanism of disease - clinical manifestation |
pemphigus vulgaris
target antigen: proteins in intercellular junctions of epidermal cells mechanism of disease: Ab-mediated activation proteases clinical manifestation: skin vesicles |
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Goodpasture's syndrome
- target antigen - mechanism of disease - clinical manifestation |
Goodpasture's syndrome
target antigen: protein in lung alveoli and glomeruli mechanism of disease: complement and FcR-mediated inflammation clinical manifestation: nephritis, lung hemorrhage |
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Rheumatic fever
- target antigen - mechanism of disease - clinical manifestation |
Rheumatic fever:
target antigen: strept cell wall Ag mechanism of disease: inflammation, macrophage activation clinical manifestation: myocarditis, arthritis |
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Myasthenia Gravis
- target antigen - mechanism of disease - clinical manifestation |
Myasthenia Gravis
target antigen: AChR mechanism of disease: antibody inhibits ACh binding down regulates receptors clinical manifestation: muscle weakness, paralysis |
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Graves' disease
- target antigen - mechanism of disease - clinical manifestation |
Graves' disease
target antigen: TSHR mechanism of disease: antibody-mediated stimulation of TSHRs clinical manifestation: hyperthyroidism |
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Pernicous anemia
- target antigen - mechanism of disease - clinical manifestation |
Pernicious anemia
target antigen: intrinsic factor mechanism of disease: neutralization of intrinsic factor, decrease absorption B12 clinical manifestation: abnormal erythropoiesis, anemia |
