The aim of this study was to ascertain the characteristics of a Trichinella spiralis cathepsin X (TsCX) and its role on larval invasion of intestinal epithelial cells (IECs). The full-length of TsCX cDNA sequence was cloned and expressed in Escherichia coli BL21. The results of RT-PCR, IFA and Western blot revealed that TsCX was expressed at T. spiralis muscle larvae (ML), intestinal infective larvae, adult worm and newborn larvae, and it was located in whole worm section. The results of Far western and confocal microscopy demonstrated that there was a specific binding of rTsCX and IEC, and the binding site was located within the IEC cytoplasm. rTsCX promoted T. spiralis larval invasion of mouse IECs while anti-rTsCX antibody inhibited larval invasion into the IECs. Silencing TsCX by specific siRNA reduced the TsCX expression and larval invasive capacity. These results indicated that TsCX specifically binds to IECs and promotes larval invasion of intestinal epithelia, and it might be a potential target of vaccines against enteral stages of T. spiralis.

本研究的目的是确定旋毛虫组织蛋白酶 X (TsCX) 的特征及其对肠上皮细胞 (IEC) 幼虫侵袭的作用。全长 TsCX cDNA 序列被克隆并在大肠杆菌BL21中表达。RT-PCR、IFA和Western blot结果表明，TsCX在旋毛虫肌肉幼虫（ML）、肠道感染性幼虫、成虫和新生幼虫中均有表达，并且位于整个蠕虫切片中。Farwestern 和共聚焦显微镜的结果表明，rTsCX 和 IEC 存在特异性结合，结合位点位于 IEC 细胞质内。rTsCX 促进了旋毛虫小鼠 IECs 的幼虫侵入，而抗 rTsCX 抗体抑制幼虫侵入 IECs。通过特定 siRNA 沉默 TsCX 降低了 TsCX 表达和幼虫侵袭能力。这些结果表明，TsCX特异性结合的IEC并促进肠上皮细胞的入侵幼虫，并且它可能是反对的肠内阶段疫苗的潜在靶标旋毛虫。