Immunoproteomic profile of Trichinella spiralis adult worm proteins recognized by early infection sera

Abstract

Background: Trichinellosis, a widespread zoonosis, is regarded as an emerging or reemerging disease. Effective treatment and prognosis of trichinellosis depends on early diagnosis of the infection. The objective of this study was to identify sensitive and specific antigens for early diagnosis or effective vaccine antigens for preventing infection. Methods: The somatic proteins of T. spiralis adult worms were separated by two-dimensional gel electrophoresis (2-DE). The separated proteins were probed with early infection sera from swine or mice infected with T. spiralis for 7 days. The primary immunoreactive spots were characterized by MALDI-TOF/TOF-MS analysis in combination with bioinformatics. The identified proteins were annotated using WEGO based on their functions. The immunodominant protein was chosen for expression as recombinant protein in E. coli and the purified recombinant protein was used to confirm its antigenicity by Western blot with the same infection sera. Results: Approximately 300 spots were separated by 2-DE, with molecular weights ranging from 10 to 130 kDa, and pI values ranging from pH 4 to 10. The sera from swine and mice infected with T. spiralis for 7 days recognized 64 proteins. MALDI-TOF/TOF-MS analysis identified 55 proteins, some with different isoforms. Finally, 40 individual immunoreactive proteins were obtained with a wide range of biological functions. Several proteins, such as heat shock protein 70, 14-3-3 protein, and cysteine protease could be used as immunodiagnostic or vaccine antigens. Among these identified proteins, the highly immunodominant Ts14-3-3 was chosen for expression in E. coli and purified recombinant Ts14-3-3 was able to be strongly recognized by the same T. spiralis infected sera used for identifying these antigens, therefore the most promising antigen for early immunodiagnosis of Trichinella infection. Conclusions: A total of 64 proteins from the adult worm were recognized by early infection sera from swine and mice infected with T. spiralis for 7 days. Several proteins, are of particular interest as immunodiagnostic or vaccine antigens, especially with Ts14-3-3 as most promising due to its highly immunogenicity during early infection, expressed protein can be recognized by Trichinella early infection sera and the native Ts14-3-3 expression in both adult and larval stages.