Tolerance induction in immunologically intact adult rats with allo-geneic spleen cell transfusion from dexamethasone-treated rats

摘要

Objective:To investigatewhetherdonor-specifictolerancecanbe inducedin adultratswithintactimmune system.Methods:AdultBN andDA ratswereusedas donorsandLewisratsas recipients.Donorratsweretreatedwith dexamethasone(DEX)intraperitoneallyeitherpriorto theirsplenectomyor priorto heartprocurement.Therecipientsei-therreceivedspleencelltransfusionfromDEX-treateddonors(DEX-SPC)2weeksbeforecardiactransplantation,or di-rectlyunderwentcardiactransplantationwithgraftsfromDEX-treateddonors(DEX-GRAFT),or receivedcombined treatmentof both(DEX-SPC+DEX-GRAFT).InonegrouptherecipientswerealsotreatedwithDEXbeforeDEX-SPC transfusionand perioperatively.Results:Significantdonor-specificprolongationof graftsurvivalwas observedin DEX-SPCgroupand evenlongergraftsurvivalfoundin recipientswithcombinedtreatmentof DEX-SPCand DEX-GRAFT.However,whentherecipientswithcombinedtreatmentweretreatedwithDEXbeforeandaftertransfusionand perioperatively(DEX-SPC+DEX-GRAFT+Recipient-DEX),thegraftsurvivalwasdecreased.Conclusion:Donor-specif-ictolerancecanbe inducedinimmunologicallyintactadultanimalsby intravenousdonorlymphocytetransfusion,indicat-ingthattoleranceor rejectionof an antigenmaynotbe decidedby theselfor non-selfnatureof theantigenor by thede-velopmentalstagesof therecipients,butcanbe verylikelyto be relatedto thedown-regulationof dendriticcellnumberor functionthatresultinfailureof supplyingcostimulationsignals.