应用供体抗原特异性CD4+CD25+ Treg细胞延长大鼠移植肾的存活

背景：随着磁分选技术的完善，体外分选、扩增足量的对移植抗原具有特异性的细胞已成为可能，但就其在体内应用剂量及免疫耐受的效能问题目前鲜有报道。 目的：探索供体抗原特异性CD4+CD25+Treg细胞在体内应用诱导移植免疫耐受的量效关系。 方法：以SD大鼠为供体、Wistar大鼠为受体，建立同种异体肾移植动物模型；体外分选、富集Wistar大鼠脾脏CD4+CD25+Treg细胞，并诱导其对SD大鼠供体抗原的特异性表型；根据不同数量(2×105、5×105、1×106、2×106)供体抗原特异性CD4+CD25+Treg细胞在肾移植中单剂量尾静脉注射，并以未注射组为对照。术后15 d分析移植肾脏存活状况。术后4，9，15 d采血检测各组肌酐水平，同时进行移植肾脏病理检查，按照Banff Schema标准进行诊断，并根据Watanabe的方法进行半定量评分。 结果与结论：术后15 d内对照组死亡率最高83.3%，2×105组次之66.7%，2×106组为58.3%，5×105组为33.3%，1×106组则全部存活；各实验组术后4，9，15 d血肌酐水平均明显低于对照组(P < 0.05，P < 0.01)；术后第9，15天，2×105组、5×105组血肌酐水平均明显高于1×106组、2×106组(P < 0.05)；术后第4，9，15天移植肾脏病理检查的半定量评分结果显示，各时间段5×105组、2×105组与对照组间差异无显著性意义，各时间段1×106组与2×106组优于对照组 (P < 0.05)。结果初步证实供体抗原特异性CD4+CD25+Treg细胞受体内应用能够改善大鼠移植肾功能，延长移植肾存活时间，1×106为相对理想的单次应用剂量。

Donor antigenic specificity CD4+CD25+Treg cells prolong the survival of allograft kidney in rats

BACKGROUND: the development of magnetic separation technique, it is feasibility to in vitro sort and amplify CD4+CD25+Treg cells for transplantation; however, the application dosage and immune tolerance have been less reported yet. OBJECTIVE: To investigate dose-effect relationship of CD4+CD25+Treg cells during allograft transplantation. METHODS: SD rats which were considered as the donors and Wistar rats as receptors were used to establish allograft kidney transplantation models. CD4+CD25+Treg cells were separated from splenic cells of Wistar rats and induced phenotype of donor antigenic specificity in vitro. According to the quantities of CD4+CD25+Treg cells injecting through tail vein during the operation of allograft kidney transplantation, models were rolled into four experiment groups: group 1 (2×105), group 2 (5×105), group 3 (1×106), and group 4 (2×106). The models out injection were considered as controls. Survival status of kidney was detected at day 15 postoperatively; creatinine level and pathological changes were detected at days 4, 9 and 15 according to Banff Schema diagnostic standard; semi-quantitative scores were measured Watanabe technique. RESULTS AND CONCLUSION: The death rate was the highest in control group (83.3%), and then group 1 (66.7%), group 4 (58.3%), and group 2 (33.3%); but rats in the group 3 were all survival. Creatinine level in experimental groups was significantly less than control group at days 4, 9, and 15 postoperatively (P < 0.05, P < 0.01); the creatinine levels in the group 1 and group 2 were significantly greater than in the group 3 and group 4 at days 9 and 15 postoperatively (P < 0.05). Semi-quantitative scores demonstrated that there was no significant difference between group 2 and group 1; but the scores in the group 3 and group 4 were significantly greater than control group (P < 0.05). The results indicated that CD4+CD25+Treg cells could improve kidney function following transplantation, and prolong survival time of transplanted kidney. The 1×106 was the best dosage for application.