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35 Cards in this Set
- Front
- Back
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what are the components of Innate immunity, cell medicated, humoral?
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Cell mediated-neutrophils (early phagocytosis and killing of microbes, macrophages (efficient phagocytosis and killing of microbes, release of cytokines that stimulate inflammation
NK cells- lysis of infected cells, activation of macrophages Circulating effector proteins, complement (killing of microbes, opsonization of microbes, activation of leukocytes (WBC) Mannose-binding lectin-opsonization of microbes activation of complement (lectin pathway) C-reactive protein (pentraxin)-opsonization of microbes, activation of complement TNF, IL-1, chemokines, inflammation IFN-alpha, beta -resistance to viral infection IFN-y- macrophage activation IL-12-IFN-y production by NK cells and T-cells IL-15-proliferation of NK cells IL-10, TGF-beta-control inflammation |
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why do mast cell degranulate
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Tissue damage microbes enter, mast cells degranulate (by physical or chemical injury,cross-linking of IgE Ab, activation by complement proteins. Histamine dilates post capillary venules, activates the endothelium, and increases blood vessel permeability. This leads to local edema (swelling), warmth, redness, and the attraction of other inflammatory cells to the site of release. It also irritates nerve endings (leading to itching or pain).
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what are the stages of immune response?
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Injury (microbes enter), mast cell degranulate, histamine causes vasodialation, and vasco permability. increased permability and upregulation of adhesion molecules on endothelial cells allows diapedesis of immune cells and allows components of complement cascade to enter, increased expression of adhesion molecules allowing neutraphils to enter, neutraphils are guided by chemokine and TNF-alpha to ingest microbes and release proinflammatory substances, tissue macrophages are activated, ingest pathogen and release cytokines, DC's migrate to lymph nodes where they activate T cells.
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what receptors are on mast cells
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Fc(epsilon)R1 which binds IgE, Ag cross-links two IgE which triggers release of histamine and inflammatory mediators
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What cells have the FcER1 and what does it do?
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Mast cells, eosinophils, basophils all express receptor which binds IgE, which can bind w/o antigen
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What cells have FcyR1 and FcaR1 and what are they used for?
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Macrophages, DC's, eosinophils and neutrophils have y and a receptors that bind IgG1 and IgA, IgA2. receptors can only interact with Ab-Ag complexes, which increases killing
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what are the three types of complement activation
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classical, lectin, alternative
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what are the functions of the complement?
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recruitment of inflammatory cells (C3a and C5a do this), opsonization of pathagens by c3b, facilitating the uptake and killing by phagocytes, perforation of pathogen membrane by MACs.
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What are the steps to the complement system
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C1 is activated by binding to two antibodies (IgM or IgG) on the microbes surface. C1 then cleaves many C2 and C4 molecules. C4b attaches to microbe surface and binds w/ C2a to form C3 convertase. C3 convertase cleaves C3, into C3a and C3b. C3a increases inflammation and chemotaxis. C3b serves as an opsonin or can combine with C3 convertase (C2a,C4b, C3b) to form C5 convertase. C5 convertase cleaves C5 into a and b. C5a anaphylatoxin is a potent mediator of inflammatory response. C5b initiates the MAC complex with C6, 7, 8, and lots of C9
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how do you get C3 convertase
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C1 binds to antibodies (IgG, IgM) on microbe surface activating C1, C1 cleaves C2 and C4, C2b and C4a attach to cell surface together and form C3 convertase.
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how do you get C5 convertase?
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C3 convertase cleaves of C3 into a and b. a can be used for chemotaxis and inflammatory agent while c3b can attach to microbe as an opsonin. C3b can form a complex with C3 convertase (C2b and C4a) to form C5convertase
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how does C5 convertase make a MAC
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C5 convertase cleaves C5 into C5a and C5b. C5a is a potent anaphylatoxin, C5b initiates the assembly of the MAC by recruiting C^, 7, 8 and multiple 9s. MAC then makes transmembrane channels that lead to cell lysis.
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How do neutraphils migrate to the injured tissue
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by chemokines released by mast cells and the C3a and C5a fragments of the complement (chemotaxis)
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what are the stages of neutraphil migration during inflammation?
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Neutraphils is rolling along and its receptor ligand for selectin attaches. This brings its integrin into a high affinity state with the receptor on the endothelial cell, diapedesis (migration thru endothelium
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what do the granules of neutraphils contain?
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Cathepsin G, defensins, BPI, lysozyme, lactoferrin, proteolytic and hydrolytic NZ's
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what does cathepsin do?
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Its in neutraphil granules and it digests collagen and proteoglycans
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what do defensins do?
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they are in neutraphil granules and they insert into membranes and destabalize ion channels (work on all pathogens)
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What is BPI
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Bacterial permability increasing protein, found in neutraphil granules, they increase bacterial permability
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What are lysozyme and lactoferrin and when are they effective?
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They are bactericidal and bacteriostatic (limits growth by interfering with metabolism and replication) at low pH
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what are the main phagocytes in the body?
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neutraphils and macrophages
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What are PPR's and what properties do they have
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Pattern Recognition receptors- there is a limited #, they create a quick response, and they recognize non-self not self
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What are TLR
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Toll like receptors are a class of proteins that span the cell membrane and recognize structures on microbes. Once a TLR binds to an Ag it sends a signal using protein mediators that signal cell to mount a response
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what are the types of PRR's
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C-type lectin (mannose), scavenger receptor, TLR, these can all be involved in phagocytosis and macrophage activation
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How are microbes killed after being phagocytized
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The phagosome merges with a lysosome and Nitric oxide and ROS reactive oxygen species (oxygen ions, free radicals, peroxides)
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How are NO and ReactiveOxygenIntermiadiates made for lysosomes
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NADPH donates an electron to O2 and NO synthase converts O2 and arginine into NO-
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what happens when a TLR is triggered in a macrophage?
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Production of cytokines, and reactive oxygen intermediates
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What happens when a mannose receptor is triggered in a macrophage?
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Phagocytosis, production of cytokines and reactive oxygen intermediates,
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When sensing microbial products what cytokines do macrophages secrete?
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IL-1beta, IL-6, IL-8, IL-12, TNF-alpha
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What do IL-1beta released from a macrophage do?
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activates vascular endothelium, activates lymphocytes, local tissue destruction, increases access of effector cells.
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What does TNF-a do?
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Activates vascular endothelium and increases vascular permeability, which leads to increased entry of IgG, complement, and cells to tissues and increased fluid drainage to lymph nodes
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What does IL-6 do when released by macrophages?
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lymphocyte activation and increased antibody production
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what does IL-8 do when released by macrophages?
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chemotactic factor, recruits basophils, neutrophis, and T cells to the site of infection.
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what does IL-12 do when released by macrophages?
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activates NK cells and induces the differation of CD4 T cells into Th cells
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what does C reactive protein do?
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its levels rise during a period of inflammation due to the rise of IL-6. It binds to phosphocholine on microbes. It acts as an opsonin to macrophages and assists in complement binding to foreign and damaged cells
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what do mannose binding proteins do?
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produced by the liver, recognizes carbohydrate patterns on pathogens, binding results in the activation of the lectin pathway of the complement system, cna
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