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1、Antigen（Ag）第二章抗原ChapterⅡAntigen1.Concept2.Immunogenicityandspecificity3.Requirementsforimmunogenicity4.Typesofantigens5.SuperantigenandadjuvantsKNOWLEDGEPOINTSConcept1.Antigen(Ag)–thesubstancesthatarerecognizedbyTCR/BCRorantibodyandinduceaspecificimmuneresponse.Antigen2.PropertiesofAg-
2、⑴immunogenicity-⑵antigenicityorimmunoreactivity(reactwiththeproductsofaspecificimmuneresponse)AgTBT漿細(xì)胞致敏T細(xì)胞抗體免疫原性AgTBT漿細(xì)胞致敏T細(xì)胞抗原性抗體3.Immunogen-Asubstancethatinducesaspecificimmuneresponse.CompleteAgs：havethepropertiesofimmunogenicityandimmunoreactivity.Hapten（半抗原）：havethepropertyofimmu
3、noreactivitybutnotimmunogenicity.-Asubstancethatisnon-immunogenicbutwhichcanreactwiththeproductsofaspecificimmuneresponse.AntigenHaptensaresmallmoleculeswhichcouldneverinduceanimmuneresponsewhenadministeredbythemselvesbutwhichcanwhencoupledtoacarriermolecule.hapten+carrier→completeAg5.
4、Tolerogen,allergenTolerogen:anantigenthatinducesastateofspecificimmunologicalunresponsivenessAllergen:asubstancecapableofinducingallergyorspecifichypersensitivity.pollens,dust,drugs,andfoods…AntigenForeignnessandspecificityⅠ.Foreignness-Theimmunesystemnormallydiscriminatesbetweenselfan
5、dnon-selfsuchthatonlyforeignmoleculesareimmunogenic.Ⅱ.specificity1.epitope(antigenicdeterminant)抗原決定簇（基），表位-theportionoftheantigenthatbindsspecificallywiththebindingsiteofanantibodyorareceptoronalymphocyte.-thesizeofanepitopeisapproximatelyequivalentto5-15aminoacids.AntigenepitopeAntig
6、endescriptionexampleOneepitopehaptensManyepitopesofthesamespecificityManypolysaccharides,homopolymersManyepitopesofdifferentspecificityproteinsRepresentationofsomepossibleantigenicstructures2.thetypesofepitope▲conformationalepitope:Someepitopesformonlywhenthecriticalresiduesarebroughtt
7、ogetherinspacethroughfoldingofthepolypeptideorpolysaccharidechainintoitsnormalthree-dimensionalconformation.▲sequentialepitope:Alloftheaminoacidorsugarresiduesthatformagivenepitopearepositionedsequentiallyinthelinearsequenceofaproteinorpolysaccharideantigen.AntigenBindingsiteforantig
