最新抗原是能够刺激机体免疫系统产生特异性免疫应答10-药学医学精品资料.ppt

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1、最新抗原是能够刺激机体免疫系统产生特异性免疫应答10-药学医学精品资料1ConceptofAntigenAntigensaresubstancesthatinduceaspecificimmuneresponseandsubsequentlyreactwiththeproductsofaspecificimmuneresponse.抗原是能够刺激机体免疫系统产生特异性免疫应答、并能与相应免疫应答产物（抗体或致敏淋巴细胞）在体内外发生特异性结合的物质，也叫免疫原(immunogen)。Anantigenisamoleculethatstimulatesanimm

2、uneresponse.Thewordoriginatedfromthenotionthattheycanstimulateantibodygeneration.Wenowknowthattheimmunesystemdoesnotonlyconsistofantibodies.Themoderndefinitionencompassesallsubstancesthatcanberecognizedbytheadaptiveimmunesystem.EndogenousantigensEndogenousantigensareantigensthathave

3、beengeneratedwithinthecell,asaresultofnormalcellmetabolism,orbecauseofviralorintracellularbacterialinfection.AutoantigensAnautoantigenisusuallyanormalproteinorcomplexofproteins(andsometimesDNAorRNA)thatisrecognizedbytheimmunesystemofpatientssufferingfromaspecificautoimmunedisease.Th

4、eseantigensshouldundernormalconditionsnotbethetargetoftheimmunesystem,butduetomainlygeneticandenvironmentalfactorsthenormalimmunologicaltoleranceforsuchanantigenhasbeenlostinthesepatients.TumorantigensTumorantigensarethoseantigensthatarepresentedbytheMHCImoleculesonthesurfaceoftumor

5、cells.Theseantigenscansometimesbepresentedonlybytumorcellsandneverbythenormalones.Inthiscase,theyarecalledtumor-specificantigens(TSAs)andtypicallyresultfromatumorspecificmutation.2CharacteristicsofAntigen★Immunogenicity免疫原性Thecapacitytostimulatetheproductionofantibodiesorcell-mediat

6、edimmuneresponses.★Antigenicity抗原性（反应原性）Theabilitytobindantibody.♣Completeantigen完全抗原♣Incompleteantigen,alsoknownashapten不完全抗原，或半抗原Incompleteantigenshaveantigenicdeterminants,butcannotinduceimmuneresponsesbecausetheylackoneormoreoftheimportantattributesneededforthisfunction(oneexamp

7、leofanincompleteantigenisahapten,whichisanartificialmonovalentepitope)3PropertiesofantigenForeignnessisessentialtoimmunogenicitybecauseself-responsivecellsareeliminatedduringlymphocyteontogeny,leavingonlycellsthatrespondtonon-self,so-called"foreign"epitopes.异物性Specificity特异性Highmole

8、cularweightMolecule