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Immunology 2 - Immunology 2*the division between innate and...

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Immunology 2 **the division between innate and adaptive immune systems does NOT exist in the real world—function together Innate immunity=immunity derived from non antigen recognition of pathogens and “passive” mechanisms like barriers Adaptive immunity=immunity directed against antigens= specific Innate Adaptive Generated from germ-line encoded genes Recognizes general features of pathogens(no fine specificity) No memory of past pathogen encounters Mixture of physical barriers, chemical defences and cellular responses Present in all individuals at all times Generated by recombination of genes in somatic cells recombined≠inherited→can’t be passed on recognizes specific antigens( fine specificity) memory of past antigens cellular responses it generated as pathogen are encountered→ more adaptive immunity as you age early bacteria= some immune function (innate) sponge=self from non self mammals and vertebras= more specific immunity=adaptive immunity Epithelium: our barrier with the outside world (first barrier) specialized tissue (lungs, GI, reproductive) tight junctions= separate and seal cells= restrict movement between cells( even water) mucous and cilia= clean epithelial surfaces basement membrane= elastic like protein structure=gives cell mechanical strength goblet cells= make mucous Chemical defences in epithelium lyzozyme= in tears, saliva= degrades bacterial cell wall (peptidoglycan) → targets it for destruction and cell lyses=stronger against gram positive secretory phospholipase A2= breaks down lipid bilayer=functions by cutting hydrophobic “tails” off of phospholipids=opens up PM= functions if breaking cell wall doesn’t work defensins and cathelicidins= attracted to charged bacterial membranes=form holes in membranes= must be cleaved to activated( produced as pre-protein and releases AMPH when cleaved)..AMPH=amphitpathic= cationic hydrophilic part and hydrophobic part→ are attracted to (-) charged lipid membranes→ embeds in membrane because doesn’t like to be exposed to water→ come together and form hole= electrostatic attraction and the transmembrane electric field bring the defensin into the lipid bilayer c-type lectins = bind to unique carbohydrates found on surface of bacteria=kill bacteria by disrupting bacterial membrane= need to be cleaved and need calcium Review-Innate Immunity Barries Epithelium-cellular: Tight junctions produce strong seal between cells Goblet cells produce mucous Cilia move mucous Chemical defences: Pore-forming proteins lyse bacteria (defensins and cathelicidins) Lyzozyme degrades peptidoglycan sPLA2 degrades pathogen plasma membrane Innate Immunity-detection of Self innate immune cells have receptors that bind to protein on healthy cell that lets them know they are self other mechanisms of innate self-recognition:
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sialic acid, glycosaminoglycans, MHC-binding receptors (independent of antigen)
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