可调控表达IL-2基因骨髓基质细胞促进异基因骨髓移植小鼠免疫功能重建

The improving effect of gene engineered bone marrow stromal cell line which can induce IL-2 gene expression on immune reconstitution after bone marrow transplantation

目的 探讨可调控表达IL 2基因的骨髓基质细胞系对异基因骨髓移植小鼠免疫功能重建的促进作用。方法 构建四环素诱导的表达小鼠IL 2基因的逆转录病毒载体 ,转染包装细胞PT6 7,感染骨髓基质细胞系QXMSC1(H 2 d) ,构建可诱导表达IL 2基因的工程化骨髓基质细胞系QXM SC1tet on IL 2。受体小鼠C5 7BL 6 (H 2 b)经γ射线致死剂量照射后 ,输入供体BALB c(H 2 d)骨髓细胞1× 10 7 只 (去除T细胞 ) ,同时输注骨髓基质细胞QXMSC1tet on IL 2 5× 10 5 只。灌服多西环素 (Dox)诱导IL 2表达。于骨髓移植 (BMT)后 30d、6 0d检测小鼠脾细胞对ConA的反应强度 ,空斑形成细胞(PFC)数和迟发型超敏反应 (DTH) ,脾细胞中T辅助细胞前体频数 (HTLp)及移植后小鼠脾脏T细胞亚群CD4 + CD8+ 的比值 ,评价BMT后免疫功能的恢复情况。结果 成功建立四环素诱导IL 2基因表达的基因工程化骨髓基质细胞系QXMSC1tet on IL 2。异基因BMT、联合输注QXMSC1tet on IL 2能显著提高BMT小鼠脾细胞对ConA的反应 ,增加脾脏淋巴细胞HTLp及PFC数目 ,并使DTH反应增强 ,改善小鼠脾脏T细胞亚群CD4 + CD8+ 的比值。结论 共输注可调控表达IL 2基因的骨髓基质细胞可促进异基因移植小鼠免疫功能重建。

Objective To study the potential effect of bone marrow stromal cell line QXMSC1 engineered to secrete IL-2 to accelerate the immune reconstitution in allogeneic bone marrow transplantation mice. Methods The regulable recombined retrovirus vector was constructed firstly which contains IL-2 cDNA and then transfected bone marrow stromal cell line, established doxycycline inducible gene expression system on bone marrow stromal cell line QXMSC1tet-on-IL-2 which can induce IL-2 gene expression by Dox. The activity of IL-2 was measured under different Dox concentration. The lethally irradiated mice C57BL/6 (H-2d) were cografted allogeneic bone marrow (BALB/c, H-2d, 1×107/mice) with QXMSC1tet-on-IL-2 (5×105/mice) at same time. Dox was administrated for 15 days to induce the expression of IL-2. Lymphocyte proliferation to Con A, plaque-forming cell (PFC), delayed type hypersensitivity (DTH) frequency of helper T lymphocyte precursor (HTLp) and T cell subset CD4+/CD8+ were examined on the 30, 60 day post transplantation, respectively. Results Firstly, the gene engineered stromal cell line achieves high-level and regulatable IL-2 gene expression. The results showed that lymphocytes proliferation to ConA was increased, frequency of HTLp, the ability of DTH and PFC was improved by coinfused stromal cells QXMSC1tet-on-IL-2 on the 30, 60 day after bone marrow transplantation. Conclusion These data demonstrated that the gene engineered bone marrow stromal cell line (QXMSC1tet-on-IL-2) could improve the immune reconstitution in allogeneic bone marrow transplantation.