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41 Cards in this Set
- Front
- Back
Define innate immunity
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form of immunity that exist before exposure to pathogens; hard wired, rapid, and recognizes conserved patterns on pathogens
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4 major characteristics of innate immunity
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1. Limited repertoire of receptors
2. Ancient system 3. Intimately intertwined with the adaptive immune system 4.Invariant and constant |
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What is the major cellular response of innate immunity
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Inflammation or the Inflammatory response
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The 4 players that participate in the generation of inflammation
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Tissues, Early soluble mediators, cells, other soluble mediators
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What are the barriers to pathogen entry
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Physical (External skin and internal mucosa)
Chemical (Fatty acids, Mucus and saliva, Cationic antimicrobial peptides) |
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What are the early soluble inflammatory mediators
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Bradykinin, Histamine, Complement, Lipid mediators, Platelet activating factor
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What does bradykinin do
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Stimulates neutrophil migration, macrophage release of cytokines; induces histamine release; activates complement; vasodilation, pain, edema
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What does histamine do
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Bronchoconstriction, vasodilation, pruritis
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What does complement do
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Vasodilation, edema, opsonization
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What do lipid mediators do
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Cell activation
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What does platelet activating factor do
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Neutrophil recruitment and activation
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What are the three major C' mediated pathways
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1. Alternative pathway (pathogen surface)
2. Lectin pathway (mannose-binding lectins bind to pathogen surface) 3. Classical (Antibody binds to pathogen antigen) |
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Where are two places C' receptors are found
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Neutrophils and macrophages. These facilitate uptake by phagocytosis
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What are the two major biologic functions of C'
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Opsonization and Chemotaxis
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Which host cells are involved in innate immunity
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Neutrophils, Tissue macrophages, mast cells, immature dendritic cells, NK cells, lymphocytes
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What is the role of neutrophils in innate immunity
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Most abundant phagocytes, first cells recruited, relatively short lived
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What is the role of tissue macrophages in innate immunity
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Mature form of monocytes, can undergo division at inflammatory sites, dominant effector cells of the second stage of the innate immmune response, set the stage for adaptive immunity
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Discuss Mast cells in innate immunity
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Located on surfaces (skin, GI tract, respiratory tract, connective tissues); preformed granules of cytokines and histamine; after activation secrete TNF-a, IL-4, IL-5, IL-6, IL-8
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Which cells are usually first to interact with antigen in the skin and mucosa
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Immature dendritic cells
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What do NK cells express
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Inhibitory receptors that recognize MHC class 1. They are thus activated by target cells lacking MHC class 1
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What do macrophages and mast cells do upon phagocytosis of pathogens in the tissues?
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Synthesize and secrete a panel of soluble mediators that play a role in the local stimulation of the localized inflammatory response and also have systemic effects
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What are the major cytokines
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IL-1B, TNF-a, IL-6, IL-8, IL-12, Type 1 interferons
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What does IL-1b do
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Activates vascular endothelium, induces the acute phase
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What does Il-8 do
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Chemotactic cytokine
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What does TNF-a do
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Activates vascular endothelium, induces the acute phase response
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What does IL-6 do
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Activates lymphocytes and induces the acute phase response
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What does IL-12 do
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Activates NK cells leading to cytokine production, especially IFN-g
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What do Type 1 and a/B interferons do
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Activate NK cells to kill virus-infected cells
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What three cytokines induce the acute phase response
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IL-1B, TNF-a, IL-6
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What are acute phase proteins (ACP)
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Soluble plasma proteins secreted by hepatocytes in the liver in response to acute infection
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What two acute phase proteins enhance the fixation of C' at the pathogen surface
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C-Reactive protein (binds PC on bacteria)
Mannose-binding protein (MBP)(initiates lectin-binding C' pathway) |
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The process of leukocyte migration to sites of infection is initiated by
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Activated tissue macrophages and mast cells at the site of infection
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Activated macrophages and mast cells at the site of infection causes
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Increased vascular permeability, increases in adhesion molecule expression, secrection of cytokines and chemokines
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What is the multi-step model of leukocyte migration
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Rolling of leukocytes on the endothelium, activation of leukocytes, stable adherence to the endothelium, transmigration
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The process of leukocyte migration to sites of infection is stimulated by
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Cytokines, especially TNF-a
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What are Pathogen Associated Molecular Patterns (PAMPS)
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Conserved molecules produced only by microbes and not by the host organism
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What are Pattern Recognition Receptors (PRR)
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A set of germline encoded receptors that recognize PAMPS and thus are specific for non-self structures
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Name two common PRRs
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Toll-like Receptors and Seven transmembrane a-helical receptors
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Name 4 phagocytic receptors
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Mannose receptors, Scavenger receptors, Fc receptors, Mac-1 (integrin)
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What are two chemicals used to kill microbes
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Reactive oxygen intermediates (ROIs) and Nitric oxide (NO)
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How is NO created in macrophages
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The inducible Nitric oxide (iNOS) system
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