抗生素英文课件-Immune-System

ImmuneSystemGuardingagainstdiseaseImmuneSystemGuardingagainstThenot-so-commoncoldA“cold”isaninfectionofthemucusmembranesoftherespiratorytractbyarhinovirus.Over100rhinoviruseshavebeenidentified,whichisonereasonwhywedon’tbecomeimmuneto“thecold.”Thenot-so-commoncoldA“cold”ColdmythsColdsand“theflu”aredifferentillnesses.Noteveryrespiratoryinfectionis“theflu.”Coldsarenotcausedbygettingchilled.Thisbeliefcomesfrommedicalideasofpriorcenturies,whenitwasbelievedthatillnesswascausedbyanimbalanceof“humors,”andthatapersonwithacoldactuallyhadtoomuch“coldness.”“Feedacold,starveafever”alsocomesfrompriorcenturies,whenitwasthoughtthatpeoplewithacoldhadtoomuch“cold”and“moisture”intheirbodies,andneededfoodtoincreaseheat,whilepeoplewithfeverhadtoomuch“dryness”and“heat,”soneededlessfoodtocoolthemdown.ColdmythsColdsand“theflu”Coldvs.“Flu”(influenza)SymptomsColdFluFeverrarecharacteristicHeadachemild(sinus)strongAches&Painsslightusual,strongFatiguemild2-3weeksExhaustionneverearly,profoundStuffynoseusualsometimesSneezingusualsometimesSorethroatcommonsometimesChestdiscomfortmildcommon,strongColdvs.“Flu”(influenza)SympVirusvs.BacteriaColdsarecausedbyavirus,whichisanon-livingparticlethatcontainsgeneticmaterial,andhijacksyourcellstoreproduce.Bacteriaarelivingorganismsthatcanreproduceontheirown.Virusvs.BacteriaColdsarecaFirstlineofdefenseNon-specificdefensesaredesignedtopreventinfectionsbyvirusesandbacteria.Theseinclude:IntactskinMucusandCiliaPhagocytesFirstlineofdefenseNon-speciRoleofskinDeadskincellsareconstantlysloughedoff,makingithardforinvaderstocolonize.Sweatandoilscontainanti-microbialchemicals,includingsomeantibiotics.RoleofskinDeadskincellsarRoleofmucusandciliaMucuscontainslysozymes,enzymesthatdestroybacterialcellwalls.Thenormalflowofmucuswashesbacteriaandvirusesoffofmucusmembranes.Ciliaintherespiratorytractmovemucusoutofthelungstokeepbacteriaandvirusesout.RoleofmucusandciliaMucuscRoleofphagocytesPhagocytesareseveraltypesofwhitebloodcells(includingmacrophagesandneutrophils)thatseekanddestroyinvaders.Somealsodestroydamagedbodycells.Phagocytesareattractedbyaninflammatoryresponseofdamagedcells.RoleofphagocytesPhagocytesaRoleofinflammationInflammationissignaledbymastcells,whichreleasehistamine.Histaminecausesfluidstocollectaroundaninjurytodilutetoxins.Thiscausesswelling.Thetemperatureofthetissuesmayrise,whichcankilltemperature-sensitivemicrobes.RoleofinflammationInflammatiRoleoffeverFeverisadefensemechanismthatcandestroymanytypesofmicrobes.Feveralsohelpsfightviralinfectionsbyincreasinginterferonproduction.Whilehighfeverscanbedangerous,somedoctorsrecommendlettinglowfeversruntheircoursewithouttakingaspirinoribuprofen.RoleoffeverFeverisadefensOuch!Ouch!SpecificdefensesSpecificdefensesarethosethatgiveusimmunitytocertaindiseases.Inspecificdefenses,theimmunesystemformsachemical“memory”oftheinvadingmicrobe.Ifthemicrobeisencounteredagain,thebodyreactssoquicklythatfewornosymptomsarefelt.SpecificdefensesSpecificdefeMajorplayersThemajorplayersintheimmunesysteminclude:MacrophageTcells(helper,cytotoxic,memory)Bcells(plasma,memory)AntibodiesMajorplayersThemajorplayersSomevocabulary:Antibody:aproteinproducedbythehumanimmunesystemtotaganddestroyinvasivemicrobes.Antibiotic:variouschemicalsproducedbycertainsoilmicrobesthataretoxictomanybacteria.Someweuseasmedicines.Antigen:anyproteinthatourimmunesystemrecognizesas“notself.”Somevocabulary:Antibody:aprAntibodiesAntibodiesareassembledoutofproteinchains.Therearemanydifferentchainsthattheimmunesystemassemblesindifferentwaystomakedifferentantibodies.AntibodiesAntibodiesareassemAntigenrecognitionCellsoftheimmunesystemare“trained”torecognize“self”proteinsvs.“notself”proteins.Ifanantigen(“notself”)proteinisencounteredbyamacrophage,itwillbringtheproteintoahelperT-cellforidentification.IfthehelperT-cellrecognizestheproteinas“notself,”itwilllaunchanimmuneresponse.AntigenrecognitionCellsofthHelperTcellsHelperT-cellshavereceptorsforrecognizingantigens.Iftheyarepresentedwithanantigen,theyreleasecytokinestostimulateB-celldivision.ThehelperT-cellisthekeycelltosignalanimmuneresponse.IfhelperT-cellsaredisabled,astheyareinpeoplewithAIDS,theimmunesystemwillnotrespond.HelperTcellsHelperT-cellshBcellsB-cellsingeneralproduceantibodies.Thosewithantibodiesthatbindwiththeinvader’santigenarestimulatedtoreproducerapidly.B-cellsdifferentiateintoeitherplasmacellsormemoryB-cells.Plasmacellsrapidlyproduceantibodies.Memorycellsretainthe“memory”oftheinvaderandremainreadytodividerapidlyifaninvasionoccursagain.BcellsB-cellsingeneralprodClonalSelectionClonalSelectionRoleofantibodiesAntibodiesreleasedintothebloodstreamwillbindtotheantigensthattheyarespecificfor.Antibodiesmaydisablesomemicrobes,orcausethemtosticktogether(agglutinate).They“tag”microbessothatthemicrobesarequicklyrecognizedbyvariouswhitebloodcells.RoleofantibodiesAntibodiesr“Killer”TcellsWhileB-cellsdivideanddifferentiate,sodoT-cells.SomeT-cellsbecomecytotoxic,or“killer”T-cells.TheseT-cellsseekoutanddestroyanyantigensinthesystem,anddestroymicrobes“tagged”byantibodies.SomecytotoxicT-cellscanrecognizeanddestroycancercells.“Killer”TcellsWhileB-cells抗生素英文课件——Immune-SystemCallingahaltWhentheinvaderisdestroyed,thehelperT-cellcallsahalttotheimmuneresponse.MemoryT-cellsareformed,whichcanquicklydivideandproducecytotoxicT-cellstoquicklyfightofftheinvaderifitisencounteredagaininthefuture.CallingahaltWhentheinvaderHelpingtheimmunesystemMedicalsciencehascreatedtosystemsforaugmentingthehumanimmunesystem:AntibioticsVaccinesHelpingtheimmunesystemMedicHowantibioticsworkAntibioticshelpdestroybacteria(butnotviruses).Antibioticsworkinoneofseveralways:Slowingbacteriareproduction.Interferingwithbacterialcellwallformation.HowantibioticsworkAntibioticAntibioticmythsAntibioticsarenotantibodies.Antibioticsdonotweakenourimmunesystem.Theyhelpitbyweakeningbacteria.Humansdonotbecome“immune”toantibiotics.Bacteriathatresistantibioticsandarenotcompletelydestroyedmaymultiply,producingmoreantibiotic-resistantbacteria.AntibioticmythsAntibioticsarVaccinehistoryVariolation:Thedeliberateinoculationofpeoplewithsecretionsfromsmallpox(Variola)sores.UsedforcenturiesinAsiaandAfrica.Vaccination:InventedbyEdwardJennerin1796.Jennerknewthatdairymaidswhohadcontractedcowpoxnevergotsmallpox.Heinoculatedaboywithsecretionsfromcowpoxsores,andshowedtheboywasimmunetosmallpox.(Fromvacca,Latinforcow.)VaccinehistoryVariolation:ThHowvaccinesworkModernvaccinesarecreatedfromkilledbacteriaorviruses,orfragmentsofproteinsfromthesemicrobes.Theproteinsarerecognizedasantigensbyourimmunesystems.Thiscausesamildimmuneresponse.MemoryT-cellsandB-cellsremainreadytofightofftheillnessifitisencounteredagain.HowvaccinesworkModernvaccinVaccinemythsThefluvaccinedoesnotgiveyoutheflu.Somepeoplegetthevaccinetoolate,orcatchacoldandthinktheyhavetheflu.Vaccinesarenotlesseffectivethana“natural”infectionwiththeillness.Theimmunityisthesame,andamildresponsetoavaccineismuchlessriskythanafull-blowninfectionofmeasles.Theproposedlinkbetweenvaccinesandautismturnsouttohavebeengreatlyexaggerated.VaccinemythsThefluvaccinedButIcaughtacold...again!Becausethereareover100differentknownrhinoviruses,it’spossibletocatchcoldsagainandagain.Inaddition,coldvirusescanmutatequickly.Nosoonerdowehaveimmunitytooneformthanalongcomesanother.ButIcaughtacold...again!BEchinacea?Echinaceaissupposedto“strengthen”theimmunesystem.StudiesinpetriedishesshowedEchinaceastimulatedwhitebloodcellstoproducemorevirus-killingperoxides,butcontrolledhumantrialshavefoundnosignificanteffects.Echinacea?EchinaceaissupposeEvolutionofthefluFluvirusesalsomutatequickly.Thesameformoftheflumayhavetheabilitytoinfectseveraldifferentvertebrateanimals.Differentformsmayhybridizetheirgeneticmaterial,causingnewstrainstodevelopinasinglegeneration.EvolutionofthefluFluviruseNewFluNewFluAllergiesAllergiesareanimmunesystemreactiontoharmlessantigens.Some,suchaspollen,maygetinthroughtherespiratorysystem.Fragmentsoffoodproteinsmaygetthroughthedigestivesystem.Thenexttimetheseproteinsareencountered,theimmunesystemattacksthem.AllergiesAllergiesareanimmuAchoo!Pollenisaharmlessprotein,yetwecanbecomeallergictoit.Mostofthesymptomsarecausedbyhistaminesreleasedbymastcells.Thatiswhyantihistaminesareusedtotreatallergies.Achoo!PollenisaharmlessproAutoimmunedisordersAutoimmunedisordersoccurwhentheimmunesystemfailstorecognizeaproteinas“self”andlaunchesanattack.Multiplesclerosis,lupus,andrheumatoidarthritisareexamples.Noneofthesecanbecured,buttheycanbecontrolledwithdrugs.AutoimmunedisordersAutoimmuneCancerCanceroccurswhenthemechanismsthatcontrolcelldivisionfail,andbodycellsdivideoutofcontrol.CytotoxicT-cellscanrecognizeanddestroythesecells.Butifdivisionistoorapid,theT-cellscannotkeepup.SomecancerresearchinvolvesassistingcytotoxicT-cellsinrecognizinganddestroyingcancercells.CancerCanceroccurswhenthemSCIDSevereCombinedImmuneDeficiencyisageneticconditioninwhichoneormoregenesforproteinscrucialfortheimmunesystemaredefective.ChildrenbornwithSCIDhavenoimmunesystem.Genetherapyhasbeenusedtoinjectagoodcopyofthedefectivegeneintobloodcellsorbonemarrowcells.Inseveralcasesthishasbeeneffective,thoughitisstillexperimental.SCIDSevereCombinedImmuneDefAIDSAIDS(AcquiredImmuneDeficiencySyndrome)iscausedbyaninfectionbytheHIV(HumanImmunodeficiencyVirus),whichattacksanddestroysT-helpercells.Becauseitattackstheimmunesystemdirectly,findingavaccinehasbeendifficult.SomedrugscanslowdownHIVreproduction,butnocureexistsyet.Preventionisstillthebest“cure.”AIDSAIDS(AcquiredImmuneDefiImmuneSystemGuardingagainstdiseaseImmuneSystemGuardingagainstThenot-so-commoncoldA“cold”isaninfectionofthemucusmembranesoftherespiratorytractbyarhinovirus.Over100rhinoviruseshavebeenidentified,whichisonereasonwhywedon’tbecomeimmuneto“thecold.”Thenot-so-commoncoldA“cold”ColdmythsColdsand“theflu”aredifferentillnesses.Noteveryrespiratoryinfectionis“theflu.”Coldsarenotcausedbygettingchilled.Thisbeliefcomesfrommedicalideasofpriorcenturies,whenitwasbelievedthatillnesswascausedbyanimbalanceof“humors,”andthatapersonwithacoldactuallyhadtoomuch“coldness.”“Feedacold,starveafever”alsocomesfrompriorcenturies,whenitwasthoughtthatpeoplewithacoldhadtoomuch“cold”and“moisture”intheirbodies,andneededfoodtoincreaseheat,whilepeoplewithfeverhadtoomuch“dryness”and“heat,”soneededlessfoodtocoolthemdown.ColdmythsColdsand“theflu”Coldvs.“Flu”(influenza)SymptomsColdFluFeverrarecharacteristicHeadachemild(sinus)strongAches&Painsslightusual,strongFatiguemild2-3weeksExhaustionneverearly,profoundStuffynoseusualsometimesSneezingusualsometimesSorethroatcommonsometimesChestdiscomfortmildcommon,strongColdvs.“Flu”(influenza)SympVirusvs.BacteriaColdsarecausedbyavirus,whichisanon-livingparticlethatcontainsgeneticmaterial,andhijacksyourcellstoreproduce.Bacteriaarelivingorganismsthatcanreproduceontheirown.Virusvs.BacteriaColdsarecaFirstlineofdefenseNon-specificdefensesaredesignedtopreventinfectionsbyvirusesandbacteria.Theseinclude:IntactskinMucusandCiliaPhagocytesFirstlineofdefenseNon-speciRoleofskinDeadskincellsareconstantlysloughedoff,makingithardforinvaderstocolonize.Sweatandoilscontainanti-microbialchemicals,includingsomeantibiotics.RoleofskinDeadskincellsarRoleofmucusandciliaMucuscontainslysozymes,enzymesthatdestroybacterialcellwalls.Thenormalflowofmucuswashesbacteriaandvirusesoffofmucusmembranes.Ciliaintherespiratorytractmovemucusoutofthelungstokeepbacteriaandvirusesout.RoleofmucusandciliaMucuscRoleofphagocytesPhagocytesareseveraltypesofwhitebloodcells(includingmacrophagesandneutrophils)thatseekanddestroyinvaders.Somealsodestroydamagedbodycells.Phagocytesareattractedbyaninflammatoryresponseofdamagedcells.RoleofphagocytesPhagocytesaRoleofinflammationInflammationissignaledbymastcells,whichreleasehistamine.Histaminecausesfluidstocollectaroundaninjurytodilutetoxins.Thiscausesswelling.Thetemperatureofthetissuesmayrise,whichcankilltemperature-sensitivemicrobes.RoleofinflammationInflammatiRoleoffeverFeverisadefensemechanismthatcandestroymanytypesofmicrobes.Feveralsohelpsfightviralinfectionsbyincreasinginterferonproduction.Whilehighfeverscanbedangerous,somedoctorsrecommendlettinglowfeversruntheircoursewithouttakingaspirinoribuprofen.RoleoffeverFeverisadefensOuch!Ouch!SpecificdefensesSpecificdefensesarethosethatgiveusimmunitytocertaindiseases.Inspecificdefenses,theimmunesystemformsachemical“memory”oftheinvadingmicrobe.Ifthemicrobeisencounteredagain,thebodyreactssoquicklythatfewornosymptomsarefelt.SpecificdefensesSpecificdefeMajorplayersThemajorplayersintheimmunesysteminclude:MacrophageTcells(helper,cytotoxic,memory)Bcells(plasma,memory)AntibodiesMajorplayersThemajorplayersSomevocabulary:Antibody:aproteinproducedbythehumanimmunesystemtotaganddestroyinvasivemicrobes.Antibiotic:variouschemicalsproducedbycertainsoilmicrobesthataretoxictomanybacteria.Someweuseasmedicines.Antigen:anyproteinthatourimmunesystemrecognizesas“notself.”Somevocabulary:Antibody:aprAntibodiesAntibodiesareassembledoutofproteinchains.Therearemanydifferentchainsthattheimmunesystemassemblesindifferentwaystomakedifferentantibodies.AntibodiesAntibodiesareassemAntigenrecognitionCellsoftheimmunesystemare“trained”torecognize“self”proteinsvs.“notself”proteins.Ifanantigen(“notself”)proteinisencounteredbyamacrophage,itwillbringtheproteintoahelperT-cellforidentification.IfthehelperT-cellrecognizestheproteinas“notself,”itwilllaunchanimmuneresponse.AntigenrecognitionCellsofthHelperTcellsHelperT-cellshavereceptorsforrecognizingantigens.Iftheyarepresentedwithanantigen,theyreleasecytokinestostimulateB-celldivision.ThehelperT-cellisthekeycelltosignalanimmuneresponse.IfhelperT-cellsaredisabled,astheyareinpeoplewithAIDS,theimmunesystemwillnotrespond.HelperTcellsHelperT-cellshBcellsB-cellsingeneralproduceantibodies.Thosewithantibodiesthatbindwiththeinvader’santigenarestimulatedtoreproducerapidly.B-cellsdifferentiateintoeitherplasmacellsormemoryB-cells.Plasmacellsrapidlyproduceantibodies.Memorycellsretainthe“memory”oftheinvaderandremainreadytodividerapidlyifaninvasionoccursagain.BcellsB-cellsingeneralprodClonalSelectionClonalSelectionRoleofantibodiesAntibodiesreleasedintothebloodstreamwillbindtotheantigensthattheyarespecificfor.Antibodiesmaydisablesomemicrobes,orcausethemtosticktogether(agglutinate).They“tag”microbessothatthemicrobesarequicklyrecognizedbyvariouswhitebloodcells.RoleofantibodiesAntibodiesr“Killer”TcellsWhileB-cellsdivideanddifferentiate,sodoT-cells.SomeT-cellsbecomecytotoxic,or“killer”T-cells.TheseT-cellsseekoutanddestroyanyantigensinthesystem,anddestroymicrobes“tagged”byantibodies.SomecytotoxicT-cellscanrecognizeanddestroycancercells.“Killer”TcellsWhileB-cells抗生素英文课件——Immune-SystemCallingahaltWhentheinvaderisdestroyed,thehelperT-cellcallsahalttotheimmuneresponse.MemoryT-cellsareformed,whichcanquicklydivideandproducecytotoxicT-cellstoquicklyfightofftheinvaderifitisencounteredagaininthefuture.CallingahaltWhentheinvaderHelpingtheimmunesystemMedicalsciencehascreatedtosystemsforaugmentingthehumanimmunesystem:AntibioticsVaccinesHelpingtheimmunesystemMedicHowantibioticsworkAntibioticshelpdestroybacteria(butnotviruses).Antibioticsworkinoneofseveralways:Slowingbacteriareproduction.Interferingwithbacterialcellwallformation.HowantibioticsworkAntibioticAntibioticmythsAntibioticsarenotantibodies.Antibioticsdonotweakenourimmunesystem.Theyhelpitbyweakeningbacteria.Humansdonotbecome“immune”toantibiotics.Bacteriathatresistantibioticsandarenotcompletelydestroyedmaymultiply,producingmoreantibiotic-resistantbacteria.AntibioticmythsAntibioticsarVaccinehistoryVariolation:Thedeliberateinoculationofpeoplewithsecretionsfromsmallpox(Variola)sores.UsedforcenturiesinAsiaandAfrica.Vaccination:InventedbyEdwardJennerin1796.Jennerknewthatdairymaidswhohadcontractedcowpoxnevergotsmallpox.Heinoculatedaboywithsecretionsfromcowpoxsores,andshowedtheboywasimmunetosmallpox.(Fromvacca,Latinforcow.)VaccinehistoryVariolation:ThHowvaccinesworkModernvaccinesarecreatedfromkilledbacteriaorviruses,orfragmentsofproteinsfromthesemicrobes.Theproteinsarerecognizedasantigensbyourimmunesystems.Thiscausesamildimmuneresponse.MemoryT-cellsandB-cellsremainreadytofightofftheillnessifitisencounteredagain.HowvaccinesworkModernvaccinVaccinemythsThefluvaccinedoesnotgiveyoutheflu.Somepeoplegetthevaccinetoolate,orcatchacoldandthinktheyhavetheflu.Vaccinesarenotlesseffectivethana“natural”infectionwiththeillness.Theimmunityisthesame,andamildresponsetoavaccineismuchlessriskythanafull-blowninfectionofmeasles.Theproposedlinkbetweenvaccinesandautismturnsouttohavebeengreatlyexaggerated.VaccinemythsThefluvaccinedButIcaughtacold...again!Becausethereareover100differentknownrhinoviruses,it’spossibletocatchcoldsagainandagain.Inaddition,coldvirusescanmutatequickly.Nosoonerdowehaveimmunitytooneformthanalongcomesanother.ButIcaughtacold...again!BEchinacea?Echinaceaissupposedto“strengthen”theimmunesystem.StudiesinpetriedishesshowedEchinaceastimulatedwhitebloodcellstoproducemorevirus-killingperoxides,butcontrolledhumantrialshavefoundnosignificanteffects.Echinacea?EchinaceaissupposeEvolutionofthefluFluvirusesalsomutatequickly.Thesameformo