青岛大学基础医学院医学免疫学

会计学青岛大学基础医学院医学免疫学Section1membranousmoleculesonBlymphocyteandfunctions一、Bcellreceptor，BCRConstitutionofBCRcomplex：mIg（IgMandIgD）andIg（CD79a）/Ig（CD79b）1、mIgStructure：mIgconsistofabasicunitoffourpolypeptidechains,twoidenticalHchainsandtwoidenticalLchains.Intracellularregionisveryshort.immatureBcellsexpressmIgM，matureBcellsexpressmIgMandmIgDsimultaneously，plasmacellsdon’texpressIg.Function：specificbindingantigen2、Ig/IgStructure：Ig（CD79a）andIg（CD79b）belongtoIggenesurperfamily，consistofextracellularregion，transmembraneregionandcytoplasmaregion，IgandIgheldtogetherbydisulfidebondtoformheterogenousdimer,thenformBCR-Ig/IgcomplexwithBCR.Function：1、transducingantigen-bindingsignaltoBcell2、transferringIgfrominnerofcelltoouterofcellDistributionofBCRcomplex：matureBcellandimmatureBcellpre-Breceptorconsistsofchain、substituteLchainandIg/Ig，pre-Breceptorexpressingonthesurfaceofpro-Bcell，isreallyimportantforBcelldevelopmentinbonemarrow.1213141516171819203456789111210Lymphocyteshaveunique,clonallydistributedantigenreceptors101010101010101010101010101010101010AntibodiesBcells二、co-receptor1、CD19/CD21/CD81/CD225StructureandDistribution：Theco-receptoronthesurfaceofBcelliscomposedofCD19、CD21andCD81/CD225（Leu-13）withnon-covalentbond.ligand：C3dg,C3d,iC3bfunction：enhancethesensitivityofBcelltoantigenstimulus2、CD72Structure:BelongstoC-typelectinsuperfamily,isa45kDaII-typetransmembranousprotein.Distribution:ConstituentexpressiononeverystageBcellsexceptplasmacells.Contain2ITIMLigand：CD100,expressedonmosthemocytoblastincludingBandTcells.CD100interactingwithCD72caneliminatetheinhibitionbyCD72，enhancingtheeffectofsignal1.Function:WhenBCRscrosslink,itcaninhibitthestimulationofsignal1.三、co-stimulationmolecules1、CD40Structure:BelongingtoTNFRSFDistribution：ConstituentexpressiononmatureBcellLigand：CD40L/CD154（expressiononactivatedTcells）Function：playanveryimportantroleinBcelldifferentiationandmature2、CD80/86Structure:anothernameB7.1（CD80）/B7.2（CD86），issinglechaintransmembraneglycoproteinDistribution：expressiononactivedBcellsLigand：CD28、CTLA-1（expressiononactivatedTcells）Function：offerco-stimulatingsignalforTcellactivation（becauseBcellisAPC）3、CD27Structure：BelongingtoTNFRSF。Distribution：CD27（activatedBcells）Ligand：CD70（CD154+CD70+Tcell）Function：PlayaroleinBcelldifferentiatingtoplasmacellsBTCD27CD70CD70CD274、CD70Expression：activatedBcellsLigand：CD27（CD45RA+CD4+Tcell）Function：PlayaroleinCD45RA+CD4+TcellsdifferentiatingtoregulatoryTcellstoinhibittheproductionofAb.5、othersICAM-1、LFA-1etc.四、membrane-bindingmoleculesofmitogenLPSreceptor、PWMreceptor五、othermembranemolecules1、CD20：Distribution：expressedoneverystageBcellsexceptforplasmacells.Function：RegulatetheproliferationanddifferentiationofBcells.2、CD22：Distribution：ExpressesonBcellsspecially，anddoesn’texpressonplasmacellLigand：CD45RO、CD75（唾液酸聚糖分子）Function：BindingCD45RO、CD75，mediateinteractiononB-monocyte、B-T、B-B.3、CD32：FcRII-BSection2SubgroupofBcellsB-1cell：CD5+，appearsonindividualdevelopmentforepart，locateinperitoneum、pleuraetc.innateimmunity，playaroleinmucousmembraneimmunityAntigenofstimulating：LPS（lipidpolysaccharides）Productionantibody：IgMPolyreactivity：B-1cellantigenreceptorandantibodycanbondallkindsofantigenepitopeusingrelativelylowaffinityFunctionsofB-1cells：1、anti-microbeinfectionbyproducingantibacteriaantibody.2、clearingdegenerativeself-antigenbyproducingpoly-reactiveautoantibody3、inducingautoimmunediseasebyproducingpathogenicautoantibody.B-2cell：ordinaryBcell，CD5-，ContaintowsubsetsofMZ（marginalzone）andfollicularMZBcellisthefirstlineofdefenceFOBcellparticipateslaterantibodyresponseofTcelldependentThemostBcellinPeyer’spatches（PP）inGALTisB-2celladaptiveimmunitySimilaritiesanddifferencesofB-1cellandB-2cell性质B-1细胞B-2细胞CD5+-初次产生的时间胎儿期出生后存在部位腹膜腔、胸膜腔、肠道固有层广泛更新方式自我更新由骨髓产生自发性Ig的产生高低特异性多反应性单特异性，尤在免疫后分泌的Ig的同种型IgM>IgGIgG>IgM体细胞高频突变低/无高对碳水化合物抗原的应答是可能对蛋白质抗原的应答可能是功能参与固有免疫参与适应性免疫characterB-1B-2CD5+-Firsttimebegin初次产生的时间FetustimeAfterbirthLocationPeritoneum/pleura、intestines固有层EverywhereRenewalSelfrenewalBonemarrowSpontaneousIgproductionHighLowspecificityPolyreactivitySinglespecificity,especiallyafterimmunityIsotypesIgM>IgGIgG>IgMSomatichypermutationofIgNo/lowhighImmunitytoImmunitytoCarbohydrateyesmayImmunitytoProteinmayyesfunctionInnateimmunityAdaptiveimmunitySection3functionofBcell（一）produceantibodies1、neutralization:bacteriatoxin,pathogen2、opsonization：Ab、complement3、antibody-dependentcell-mediatedcytotoxicity（ADCC）4、activateComplement:opsonizationandlysemicrobe