NK细胞对异基因骨髓移植中移植排斥和造血及免疫重建的影响

Effects of Natural Killer Cells on Engraftment and Reconstitution of Hematopoiesis and Immunity in Mice Undergoing Allogeneic Bone Marrow Transplantation

本研究探讨自然杀伤(NK)细胞在小鼠异基因骨髓移植(allo-BMT)中对移植排斥、造血及免疫重建的影响。以C57BL/6(H-2b)小鼠为供鼠、BALB/c(H-2d)小鼠为受鼠,分别在致死剂量和非致死剂量(≤7.0Gy)全身照射(TBI)的预处理条件下进行allo-BMT,移植同时输注供鼠外周T细胞和(或)NK细胞,移植后不同时间检测受鼠外周血白细胞、骨髓CD34+细胞数和外周血淋巴细胞中CD3+细胞、CD19+细胞及供鼠来源的H-2Kb+细胞表达的百分率,并对不同移植组的存活率、植入与排斥、造血及免疫重建进行比较。结果表明:在致死剂量TBI预处理的移植中,输注NK细胞与不输注NK细胞的移植组比较,存活率显著增高(60天存活率为70%vs0.0%);白细胞数、CD19+细胞表达及骨髓CD34+细胞数恢复快;H-2Kb+细胞的表达水平高[(86.68±4.45)%vs(4·68±0·32)%]。移植后28天输注NK细胞组CD3+细胞表达水平明显低于不输注NK细胞组[(33.69±3.36)%vs(50.40±5·06)%,p<0.01],移植后60天两组比较差异无显著性(p>0.05)。在非致死剂量TBI预处理的移植中,移植后30天,异基因骨髓移植组H-2Kb+细胞表达率明显下降,移植后60天已下降至移植前水平;而输注高浓度和低浓度NK细胞的两组在移植后60天仍能检测到80%以上的H-2b+细胞表达。结论:在小鼠allo-BMT中,同种异基因反应性NK细胞可以抑制移植排斥,提高造血干细胞的植入水平,促进造血及免疫重建并增加移植受鼠的生存率。

The aim of this study was explore the effect of natural killer （NK） cells on engraftment and reconstitution of hematopoiesis and immunity in mice undergoing allogeneic bone marrow transplantation （allo-BMT）. Lethally and nonlethally irradiated BALB/c （ H-2d ） mice were transplanted with C57BL/6 （ H-2b ） bone marrow plus donor peripheral T cells and/or NK cells. Recipient CD34^＋, H-2K^b＋, CD3^＋ and CD19^＋ cells were detected by flow cytometry; peripheral blood leukocytes were counted by auto-cytometry; survival rates, engraftment, hematopoietic and immune recovery of recipients in different transplant groups were then observed. The results indicated that as compared with lethally irradiated and allo-BMT group without infusion of NK cells, the survival rate in lethally irradiated and allo-BMT group with infusion of NK cells significantly enhanced （ survival rates at 60 days were 70% and 0.0% respectively） ; leukocyte count, expression level of CD19^＋ cell and CD34^＋ cell count recovered rapidly; expression level of H-2K^b＋ cells obviously increased [ （ 86.68 ± 4. 45 ） % vs （4.68 ± 0.32 ） % ] ; expression level of CD3 ^＋ cell at day 28 after transplantation obviousty decreased [ （ 33.69 ± 3.36） % vs （50.40 ± 5.06） %, p 〈 0.011, at day 60 there was not significant difference between the 2 groups （p 〉 0.05 ）. In nonlethally irradiated and allo-BMT group without NK cell infusion, the expression level of H-2K^b＋ at day 30 after transplanetation significantly decresed, and reduced to level before transplantation at day 60; while expression of H-2K^b＋ yet could be detected with 〉 80% at day 60 after transplantation in group infused with high and low concentration of NK cells. It is concluded that in allo-BMT mice, alloreactive NK cell inhibits graft rejection, enhances engraftment, promotes the reconstitution of hematopoiesis and immunity, and increases survival rates.