负载供者凋亡细胞的受者未成熟树突状细胞可延长小鼠移植心脏的存活时间

Marked prolongation of murine cardiac allograft survival using recipient immature dendritic cells pulsed donor-derived apoptotic cells

目的 探讨吞噬供体凋亡细胞的受者树突状细胞 (DC)的功能及其在诱导同种异体小鼠心脏移植耐受中的作用。方法 应用中波紫外线照射的方法诱导供者脾细胞凋亡 ,并在体外与受者骨髓来源的DC共同培养 ,同时用核因子 κB寡聚脱氧核苷酸诱骗剂 (NF κBODNDecoy)抑制DC的成熟。建立同种异体小鼠心脏异位移植模型 ,移植术前 7d经门静脉给受者输注经上述处理的DC ,观察移植物的存活时间 ,并检测移植物内相关细胞因子基因的表达情况。结果 NF κBODNDecoy可明显抑制DC吞噬凋亡细胞后的成熟 ;经NF κBODNDecoy处理且负载凋亡脾细胞的DC可抑制T淋巴细胞增殖反应 ,且具有供者特异性 ,接受DC门静脉输注的受者 ,移植心脏的平均存活时间明显延长 ,移植心脏内白细胞介素 2及γ干扰素mRNA的水平减低 ,白细胞介素 10mRNA的水平升高 ,而输注仅负载凋亡脾细胞的DC ,移植心脏的平均存活时间未见延长 (P <0 .0 1) ,这种保护作用具有抗原特异性。结论 以NF κBODNDecoy处理的、吞噬同种凋亡细胞的受者未成熟DC可明显延长同种小鼠移植心脏的存活时间。

Objective To investigate the effect of recipient dendritic cells (DC) loaded with donor-derived apoptotic cells on inducing murine cardiac allograft tolerance. Methods Apoptosis of donor-derived splenocytes (SC) was induced by ultraviolet B irradiation(UVB). UVB-irradiated allogenic SC were co-cultured with recipient bone marrow-derived DC that maturation was inhibited by NF-κB ODN Decoy, so that could acquire tolerogenic-immature DC loaded with donor-derived apoptotic cells (Decoy Apo-SC DC). A heterotopic vascularized heart transplantation was performed from BALB/c to C57BL/6 mice, and recipients were given one injection of recipient immature (Decoy Apo-SC DC) or mature (Apo-SC DC) DC engulfed donor-derived apoptotic cells (2×10 6 cells) through the portal vein at 7 days before the heart transplantation in the absence of immunosuppression. The cardiac survival and the expression of intragraft cytokines (IL-2, IL-10 and IFN-γ) were evaluated.Results DC had potent phagocytosis of allogenic apoptotic SC (Apo-SC). NF-κB ODN Decoy inhibited engulfment of apoptotic cells-induced maturation of DC and then induced recipient tolerogenic DC. Recipient tolerogenic DC loaded with donor-derived apoptotic cells were able to cross-tolerate recipient T cells, which revealed by alloantigen-specific T-cell hyporesponsiveness in primary and secondary mixed leukocyte reaction. Injection of recipient tolerogenic DC loaded with Decoy Apo-SC DC through the portal vein at 7 days before the heart transplantation significantly prolonged vascularized heart allograft survival (MST 36.4 days versus 7 days in control group, P< 0.01; 5 days in the injection of Apo-SC DC group, P< 0.01), and the function of prolongation had donor-specificity, and led to skewing of intragraft cytokine expression toward Th2 (IL-10).Conclusion Allogenic apoptotic cells-pulsed host DC prolongs cardiac allograft survival. The mechanisms responsible for DC tolerogenicity may involve the induction of indirect cross-tolerance and the skewing of Th cytokine responses. The results suggest that recipient tolerogenic DC loaded with donor-derived apoptotic cells might have therapeutic potential in the induction of transplant tolerance.