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Download 16 Nonspecific Immune Response
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Transcript
Physiology Unit3 INNATEIMMUNITY Non-SpecificImmuneResponse InPhysiologyToday ResistancetoDisease • Bodydefensesagainstinfectiousdisease • Immunesystemhas2arms: – Innateornon-specificimmunity – Adaptiveorspecificimmunity ImmuneCells • Diversecollectionof cellsthatarefoundin blood,lymphand tissuesthroughoutthe body • Cytokines – Chemicalmessengers secretedbyimmune cells • Cells – – – – – – Leukocytes Plasmacells Macrophages Dendriticcells Lymphocytes Mastcells ImmuneCells • Leukocytes – Usebloodprimarilyfortransportandmigrateto thetissueswheretheyfunction • Plasmacells – Foundintissues(lymphnodes)wherethey differentiatefromBlymphocytes – Synthesizeandsecreteantibodies ImmuneCells • Macrophages – Foundinallorgansandtissuesstrategicallyplaced wheretheywillencountertheirtargets • Epitheliaincontactwiththeoutsideofthebody – skin,liningofdigestiveandrespiratorytract – Linebloodandlymphvessels – Tissuespecificresidentpopulations – Derivedfrommonocytes,transformintomacrophages – Passthroughwallsofcapillariestoentertissues • Diapedesisandextravasation Macrophage • • • • • • • • • KupferCells(liver) MesangialCells(kidney) SatelliteCells(PNS) Microglia(CNS) DendriticCells(skin) Monocytes DustCells(lungs) Histocytes(c.t.) Osteoclasts(bone) • Macrophagearelong lived(severalmonths) • APCrole • Removalofcellular debris • Inflammatoryresponse • Tissuerepair • Woundhealing DiapedesisorExtravasation ImmuneCells • Dendriticcells – Epitheliumincontact withtheexternal environment, – Macrophagefunction – Migratetolymphnodes • APC’s • PresenttoTCells • Messengersbetween innateandadaptive immunity Lymphocytes Recognitioncellsinspecificimmunedefensesandareessentialfor allaspectsofspecificimmuneresponses ImmuneCells • Mastcells – Foundinconnective tissues(especiallybelow epithelialsurfacesofthe body) – Moveintotissueswhere theydifferentiateand divide – Containvesiclesthat containhistamineand heparin Cytokines • Immunecellssecretemorethan100protein messengersthatregulatehostcelldivision • Involvedinnon-specificandspecificimmune defenses • Mostoftheiractionsactlocally – Paracrine/autocrineagents – Somewillcirculateinbloodandactashormoneson distantorgans • Allowcommunicationbetweendifferentimmune cellsandtimingofcascadereactions NonspecificImmuneDefenses InnateImmuneResponse • Againstall“non-self” cells • Recognizesomegeneralpropertymarkingthe invadersasforeign – Antigens • Notdependentuponexposuretodisease • Include:defensesatthebodysurfaces,the inflammatoryresponse,interferons DefensesattheBodySurface PhysicalBarriers • Skin – Watertightbarrier – Keptcleananddry – Sweatglandssecreteantibodies,lysozyme – Mostlyimpermeabletomicrobes • Certainmicrobesdrillthrough(syphillis,hookworms,manyarthropodborne pathogens) • Coughandsneezereflex • Hairsattheentranceofthenose DefensesattheBodySurface PhysicalBarriers • Mucousmembranes • Nonkeratinized epithelialmembranes, oftenciliated • Linedwithmucus • Containantimicrobial chemicals • Excellentfortrapping microbesforexpulsion DefensesattheBodySurface PhysicalBarriers • Serousmembranes • Lubricatedwithserumfrom “leakycapillaries” • Internalphysicalbarriertoinfectionofvital organs • Heart,lungs,andabdominalviscera • Similarprotectionbythemeningesofthe brainandspinalcord NonspecificChemicalDefenses • pHlevels – Gastricjuice,vaginalsecretions,urine • Lysozyme – Intears,saliva,sweat – Bindstomicrobesandpunchesholesinthecell wall – Foundingranulesofneutrophilsand macrophages NonspecificCellularDefenses • Neutrophils • FirstWBCatan infectionsite • Voraciousphagocytes • Microphage • Uselysozymesand oxygenradicalsto dissolvemicrobes NonspecificCellularDefenses • Eosinophils • Slightlyphagocytic • Majorroleininfections involvingeukaryotic parasites(worms) • Alsoinvolvedincertain allergies,dissolving clots,detoxifying foreignsubstances NonspecificCellularDefenses • Basophils • Similartomastcellsof looseconnectivetissue • Granulescontain – Heparin – Histamine • vasodilator,increases capillarypermeability • Importantto inflammation,especially relatedtoallergies NonspecificCellularDefenses • Monocytes • Transformwhenactivated tomacrophages • “Eat”microbesand cellulardebris • Storedintheredpulpof thespleen • Linknonspecificbody defensestothespecific immuneresponses – APC NonspecificCellularDefenses • NaturalKillers • NKCells • “lymphocytelikecell”,butnot immunologicallyspecific • Performstumorsurveillance Inflammation • Localresponsetoinfectionorinjury • Functions – Todestroyforeigninvaders – Preparefortissuerepair • Keymediatorsarephagocyticcells – Neutrophils,macrophages,dendriticcells Inflammation • Inflammationaccompaniesmanyimmune responses • Involvesphagocytosisandmanyimmune processes • FirstWBCatinfectionsite:neutrophil • Stimulatedbythepresenceofinfectionor allergen • Signs:pain,heat,swelling,redness Inflammation 1. Infectionorinjurycausesreleaseofchemicals 2. Localvasodilation 3. Increaseinproteinpermeabilityresultingin diffusionofproteinandfiltrationoffluidinto interstitialfluid 4. Diapedesis:movementofleukocytesfromvenules intointerstitialfluidofinfected/injuredarea 5. Destructionofbacteria 6. Tissuerepair ComplementPathway • A“suite” (orfamily)ofplasmaproteins • Extracellularkillingofbacteriawithoutphagocytosis • Sequentiallybindtobacteria,formingapore,causing lysis • Antibodiesactivatethefirstcomplementprotein (C1) • Someformopsonins – Makemicrobes“tasty” – Chemicalattractantforphagocytes – Moleculethatenhancesphagocytosis Complement Complement Interferons • Nonspecificchemicaldefensesinplasma • Interferon familyofcytokines • Nonspecificallyinhibitviralreplicationincells – Protectionforhealthycellsagainstnewlyreleased viruses – Host(tissue)specific,notvirusspecific • Releasedbyvirusinfectedbodycells InterferonAction
