Proteomic analysis of the changed proteins of Trichinella spiralis infective larvae after co-culture in vitro with intestinal epithelial cells

The purpose of this study was to determine the protein changes in Trichinella spiralis muscle larvae (ML) after in vitro co-culture with intestinal epithelial cells, and to analyze the changed proteins. Muscle larvae were incubated with HCT-8 cells for 18 h and the ML soluble proteins were analyzed by SDS-PAGE and Western blot. Results showed that seven additional protein bands (123, 77, 58, 36, 30, 28 and 21 kDa) were recognized by sera from infected mice after culture with HCT-8 cells. Three protein bands (97, 51 and 23 kDa) were not recognized by infection sera compared with proteins from ML incubated in RPMI-1640 medium only. Three bands (58, 36 and 21 kDa) were excised from gels, digested with trypsin, and identified by liquid chromatography and tandem mass spectrometry (LC–MS/MS) combined with bioinformatics. In total, 211 kinds of proteins were identified, and numerous enzymes (e.g. metallo- and serine proteases, cysteine proteinases) were found to be highly expressed.