抗体(分得很细).ppt

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1、AntibodiesSecretedbyBlymphocytesGreatdiversityandspecificity:>109differentantibodies;candistinguishbetweenverysimilarmoleculesTagparticlesforclearance/destructionProtectagainstre-infection(vaccines)AntibodyStructureIgdomain:110aminoacids;globulardomai

2、nusedinmanyproteins;Variabledomains,Constantdomains,HingeFab:fragmentantigenbindingFc:fragmentcrystallizable(effectorfunctions)©NewSciencePressLtd.2003TheImmunoglobulinSuperfamily(afewexamples)VariabilityinantibodiesisclusteredintheloopsintheVariabled

3、omainsoftheheavyandlightchains(green);theseregionsareresponsibleforbindingtoantigenAntibodyClasses:Structure©NewSciencePressLtd.2003AffinityandAvidityAffinity:thestrengthofbindingbetweenasinglebindingsiteandasingleligand[A][B][AB]Avidity:thestrengthof

4、bindingbetweenamoleculeandacomplexligand,e.g.iftherearemultiplebindingsitesthentheaviditymaybeincreasedbyincreasingthenumberofbindingsitesorbyincreasingtheaffinityofthosebindingsitesKD=AffinityandAvidityIIIgMisproducedearlyinanimmuneresponsewhentheaff

5、inityforantigenoftenislow;asanimmuneresponsecontinues,antibodyaffinityisimproved,thisiscombinedby“classswitching”totheuseofsmallermolecules(IgG,IgEandIgA).Theincreasedaffinitycompensatesforthedecreaseinnumberofbindingsitesinmaintainingtheoverallavidit

6、yforantigen©NewSciencePressLtd.2003MonoclonalAntibodiesSingleantibody(allsameHandLchains)MadebyfusionofBcellstoatransformedcelllineoftheplasmacelltypeandselectionfor“hybridomas”thatproduceantibodywiththedesiredpropertiesStandardized,unlimitedreagentfo

7、rdiagnosisortherapy(humanantibodiesor“humanized”antibodiescanbemade)Polyclonalvs.MonoclonalAntibodiesImmunizeIndividualSerumPolyclonalantibodies7+daysPurifyantibodiesBlymphocytes3daysImmortalize“hybridoma”cDNAcloningMonoclonalAntibodiesGenerationofMon

8、oclonalAntibodies©NewSciencePressLtd.2003MonoclonalantibodiesusedinmedicineStandardized,unlimitedreagentsfordiagnosisortherapy(humanantibodiesor“humanized”antibodiescanbemade)©NewSciencePressLtd.2003GenerationofantibodydiversityHowdowemake>109