Characterization of a chymotrypsin-like enzyme from Trichinella spiralis and its facilitation of larva penetration into the host's enteral epithelial cells

Abstract The aim of this work was to identify the molecular characteristics of a chymotrypsin-like enzyme from Trichinella spiralis (Tschy) and its facilitation of larval penetration into enteral epithelial cells (EECs). The complete Tschy cDNA sequence was cloned and expressed in Escherichia coli BL21. RT-PCR, IIFA and western blotting showed that Tschy was expressed at the T. spiralis muscle larvae (ML), intestinal infective L1 larvae (IL1), adult worms (AW) and embryo stages and was primarily located in the stichosome of this parasite. The results of ELISA, IIFA and Far-western assays showed that there was a specific binding between rTschy and EECs, and the binding was dependent on the dose of both rTschy and EEC proteins. Confocal microscopy demonstrated that the binding was located in the EEC cytoplasm. rTschy facilitated T. spiralis larval penetration of EECs, and anti-rTschy antibodies impeded the larval intrusion of EECs. These results demonstrate that Tschy facilitated the larval intrusion of the host's enteral epithelium and could be a candidate molecular target for vaccine against the enteral invasive phase of T. spiralis.