Abstract: Objective To explore the possible mechanisms by which Schistosoma japonicum heat shock protein 60 （SjHSP60） enhances CD4+CD25+ regulatory T cell （Treg） immunosuppressive function. Methods An in vitro method was used to investigate the effect of SjHSP60 on Treg immunosuppressive activity. Co?cultures in transwells and in vitro suppression assay were performed to investigate how SjHSP60 enhanced the immunosuppressive function of Tregs. Intracellular cytokine staining combined with flow cytometry was used to detect Treg?expressing IL?10 and TGF?β， and flow cytometry was also used to analyze the expressions of Foxp3 and CTLA?4 in Tregs. Results SjHSP60 enhanced the immunosuppressive function of Tregs. Soluble cytokines IL?10 and TGF?β mediated inhibitory activity of SjHSP60?triggered Tregs. SjHSP60 induced significant increases in both IL?10 and TGF?β expressions of Tregs. Further investigation showed significant increased Foxp3 and CTLA?4 in SjHSP60?trggered Tregs. Conclusion SjHSP60 enhances Treg immunosuppressive function by promoting the expressions of IL?10 and TGF?β， possibly due to SjHSP60?mediated induction of Foxp3 and CTLA?4 in Tregs.

Key words: Schistosoma japonicum； Heat shock protein 60； CD4+CD25+ regulatory T cell； Immunosuppressive function； IL?10； TGF?β

摘要： 目的 探讨日本血吸虫热休克蛋白60（SjHSP60）增强小鼠CD4+CD25+调节性T细胞（Treg）免疫抑制功能的可能机制。 方法 采用体外研究探索SjHSP60对Treg细胞功能的影响，通过体外细胞增殖实验检测SjHSP60促进Treg细胞免疫抑制功能增强的途径，利用流式细胞术检测Treg细胞表达IL?10和TGF?β的水平以及Treg细胞Foxp3和CTLA?4表达水平。 结果 体外实验证实，SjHSP60可增强Treg细胞的免疫抑制功能（t = 6.466，P = 0.006）；体外细胞增殖实验表明，SjHSP60刺激后的Treg细胞可通过分泌可溶性细胞因子IL?10（t = 7.363，P = 0.002）和TGF?β（t = 11.262，P = 0）发挥免疫抑制功能；流式细胞术检测显示，SjHSP60刺激后的Treg细胞IL?10（t = 12.367，P = 0）、TGF?β（t = 8.431，P = 0.001）、Foxp3（比例：t = 5.225，P = 0.006；平均荧光强度：t = 8.319，P = 0.001）和CTLA?4（比例：t = 3.518，P = 0.024；平均荧光强度：t = 4.164，P = 0.014）表达水平显著增加。 结论 SjHSP60可通过促进Treg细胞表达IL?10和TGF?β增强其免疫抑制功能，并可能与SjHSP60诱导Treg细胞表达Foxp3和CTLA?4有关。

关键词: 日本血吸虫；热休克蛋白60；CD4+CD25+调节性T细胞；免疫抑制功能；IL?10；TGF?β