Abstract
Objective To explore the role of donor spleen ceils(Sos)(including transfusion pathway)combined with anti CD154 monoclonal antibody(mAb)on bone marrow transplantation in nonmyeloablative pre-conditioning regimen for induction of aUngeneic mixed chimerism and donor-specific immune tolerance.Methods Lewis rats(Rt11)were used as donors,Wistar-Furth rats(Wistar,Rt1u)as recipients,and Sprague-Oawley(SD)rats as the third party donors.Scs and bone marrow cells(BMCs)were harvested from donor Lewis rats.Recipient Wistar rats were randomly divided into 4 groups,20 rats in each group.In group A,dorsum penis vein(i.v.)injection of Lewis rats 2×108 Scs on day 0 alone.In group B,portal vein(P.V.)injection of Lewis rats 2×108 Scs on day 0 alone.In group C,P.V.injection of Lewis rats 2×108 Scs on day 0,in combination with i.v.injection of Lewis rats 1×108 BMCs on day 3.In group D,P.V.injection of Lewis rats 2×108 Scs on day 0,intraperitoneal injection of 3 μg AH.F5 (hamster anti-rat CD154 mAb)2 h later,in combination with i.v.injection of Lewis rats 1×108 BMCs on day 3.Tolerance was assessed by stimulation index(SI)of one-way mixed lymphocyte reaction(MLR).Rt11 positive chimersim in recipient spleen and thymus was measured by flow cytometric(FACS)analysis on the day 20,40.In rats in group D were additionally subjected to chimerism detection on the day 100.Results SI in group D on the day 20,and 40 was significantly lower than other groups(4.43±0.19,4.97±0.25,P <0.01).The results of Rtl1+ assay revealed that there was no chimersim in group A.While chimersim was transient and lower in groups B and C on the day 20,and rapidly decreased.Only group D had stable and higher level chimerism in spleen(32.40±3.29)%,(23.06±3.77)% and thymus(31.08±2.60)%,(24.52±3.22)% on the day 20,and 40.Furthmore,long-term chimerism (> 100days)was observed in the group D.Conclusion High level of ehimerism(> 30% in peripheral spleen and > 20% in central thymus)provides the foundation to BMCs to play a critical role in the induction or maintenance of tolerance.P.V.injection of Sos and anti CD154 mAb,plus i.v.injection of BMCs had synergistic effect to induce donor-specific tolerance and establish stable allogeneic mixed ehimersim,without participation of megadose BMCs,myleosuppressive drugs and irradiation. Key words: Bone marrow transplantation; Spleen cells; CD154; Chirnerism; Immune tolerance
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