转化生长因子β1基因修饰的小鼠树突状细胞在移植体内的迁移与生存

In vivo migration and survival of donor derived dendritic cell progenitors genetically modified using an adenoviral vector encoding cDNA for TGFβ1

目的观察β型转化生长因子（ＴＧＦβ１）基因修饰的Ｂ１０小鼠骨髓树突状细胞（ＤＣ）在Ｃ３Ｈ小鼠体内的迁移和存活，以探讨ＤＣ生物学特性与移植耐受性的关系。方法从Ｂ１０小鼠骨髓分离ＤＣ前体细胞，在粒细胞巨噬细胞集落刺激因子＋β型转化生长因子（ＧＭＣＳＦ＋ＴＧＦβ）条件下培养增殖（ＤＣ１），并转导ＡｄＬａｃＺ（ＤＣ２）或ＡｄＴＧＦβ１（ＤＣ３）。每组５×１０５个细胞注入Ｃ３Ｈ小鼠后掌皮下，分别于第１、２、７及１４天取淋巴器官，以免疫组织化学方法检测ＩＡｂ阳性细胞的分布及数量。结果各组ＤＣ在Ｃ３Ｈ小鼠体内的迁移及分布均相似，即ＩＡｂ阳性细胞首先出现在窝淋巴结被膜下，继而迁入脾的Ｔ细胞依赖区和边缘区，第７天脾内阳性细胞数达顶峰。与ＤＣ１组相比，ＤＣ２在脾内的阳性细胞数减少，ＤＣ３阳性细胞数在各时间点都为最高。结论ＤＣ经转导ＡｄＬａｃＺ，可增加其免疫活性，使宿主加速排斥反应；而转导ＡｄＴＧＦβ１可使ＴＧＦβＤＣ表达ＴＧＦβ１，维持ＤＣ于功能不成熟状态，从而提高宿主的耐受性。

Objective To investigate the migration and survival of B 10 mouse bone marrow (BM) derived DCs in C 3H mice and if genetic modification of these DCs to overexpress TGF β1 may potentiate their tolerogenicity. Method B 10 mouse BM derived DCs were propagated in GM CSF and TGF β (DC 1), transduced DC 1 with replication deficient Ad vectors encoding genes for LacZ (DC 2) or TGF β1 (DC 3). Cells of different groups were injected into one footpad of C 3H mice. The mice were sacrificed on days 1, 2, 7, and 14, and spleens, thymuses, popliteal and mesenteric lymph nodes removed and stained with anti IA b mAb. The incidences of B10 DC were determined by the mean number of IA b positive cells with dendriform morphology per low power field (×100). Results Transduction with Ad LacZ or Ad TGF β1 did not affect DC migration or distribution in C 3H recipients, i. e. IA b+ cells were first observed under the capsule of popliteal LN (peak at d1), then migrated into the marginal T dependent area of spleens (peak at d7), and were found occasionally in the thymus. Transduction of Ad LacZ reduced the numbers of IA b+ cells identified in both LN and spleens at all time points post injection, compared with injection of unmodified control DC, suggesting that Ad transduction itself can affect DC life span in allogeneic recipients. Overexpression of TGF β1 by transduction of Ad TGF β1 not only fully reversed the reduction of DC numbers induced by Ad transduction, but also prolonged the life span of DC in spleen, as shown by the 2 fold increase in number of IA b+ cells in spleen at d14 compared with control DCs. Conclusion Mouse BM derived TGF β DCs can be transduced to express TGF β1 using an adenoviral vector, and exhibit the same migration characteristics as unmodified DC. The survival of TGF β gene transduced DCs appears to be enhanced compared with unmodified or LacZ gene transduced DCs.