供体抗原特异性CD4^+ CD25^+ Treg细胞对肾移植大鼠免疫状态的影响

Effect of donor antigenic specificity CD4^+ CD25^+ Treg cells on immune status of rat renal allograft

目的研究供体抗原特异性CD4+CD25+调节性T细胞(Treg)对肾移植后大鼠免疫状态的影响。方法常规分离Lewis和F344大鼠脾脏淋巴细胞,然后将Lewis大鼠淋巴细胞负载F344大鼠抗原,然后从负载抗原后的Lewis大鼠淋巴细胞悬液中用MACS磁珠分选法分离纯化供体抗原特异性CD4+CD25+Treg细胞,并用流式检测分选Treg细胞纯度以及RT-PCR检测分选细胞的Foxp3基因表达。以F344、Lewis大鼠分别为供、受体建立同种异体肾移植动物模型,将供体抗原特异性Treg细胞经尾静脉注射入受者体内(治疗组,n=8),选取未注射组为对照组(n=8)。于术前1d,术后15d检测移植后4组大鼠血清IL-10、IgG,并于术后15d MTT法检测受体脾细胞对供体抗原刺激的反应。结果所分选之CD4+CD25+Treg细胞成功获得供体抗原特异性,对供体抗原的抑制率(IR)为85.4%,并检测到Foxp3表达。移植前治疗组和对照组大鼠血清中均无法检测到IL-10浓度。术后15d治疗组血清IL-10与对照组比较,明显增高(P<0.01)。对照组在术后15d血清IgG浓度已经显著升高,较术前差异有统计学意义(P<0.05)。而治疗组术后15d血清IgG浓度与术前相比有所降低,与术前相比差异无统计学意义(P>0.05),但与对照组相比较均差异有统计学意义(P<0.05)。治疗组对供体脾细胞的刺激反应也明显低于Ⅰ组(P<0.01)。结论供体抗原特异性CD4+CD25+Treg细胞能显著促进体内IL-10的产生以及抑制免疫球蛋白IgG的产生,并且可特异性抑制受体对供体抗原的免疫反应。

Objective To study the effect of donor antigenic specificity CD4^＋ CD25^＋ Treg cells on immune status of rat renal allograft. Methods Lewis lymphocytes cells isolated were loaded with antigen of F344 rats. F344 antigenic specificity CD4^＋ CD25^＋ regulatory T cells of Lewis rats were classified by the MACS. Detecting the purity and the expressed of Foxp3 of prepared cells by way of FACS and RT-PCR. 16 Wister rats underwent unilateral nephrectomy and heterotopic transplantation with F344 kidneys. Then,they were divided into two groups. The treatment group（n= 8） moulds were injected CD4^＋ CD25^＋ Treg cells through tail vein in the operation of allograft kidney transplantation ,while the controls（n=8） without injection. 15 days after transplantation, one-way mixed lymphocyte reaction（MLR） of the recipients to donors lymphocytes performed by MTT among two groups were compared. Serum IL-10 levels and Serum IgG were measured on ld, 15d posttransplantation. Results The serum IL-10 was higher levels in control group than in treatment group at postoperative 15d. The serum IgG was lower levels in treatment group than in control group at posttransplantation 15d. The stimulation index（SI） of MLR for SPC of donors in treatment group was lower than in control group （P〈0.01）. Conclusion Donor antigenic specificity CD4^＋ CD25^＋ Treg cells can not only promote secretion of IL- 10 and inhibit secretion of IgG. but also specifically suppress recipient immune response to donor antigen.