The Trichinella genus poses an interesting puzzle for researchers, having diverged very early in the evolution of the nematodes. The Trichinella spiralis proteome is a cosmopolitan and well-studied model of Trichinella; however, Trichinella britovi also circulates in the sylvatic environment and both species infect humans, resulting in the development of trichinellosis. Few experiments have examined the proteins belonging to the T. britovi proteome. The aim of the present study was to compare the protein expression profiles of crude extracts of T. spiralis and T. britovi muscle larvae using a highly-sensitive two-dimensional differential in-gel electrophoresis (2D DIGE) technique coupled with 2DE immunoblotting. Selected immunoreactive protein spots were then identified by liquid chromatography coupled with mass spectrometry analysis (LC-MS/MS), and their function in Trichinella and the host-parasite interaction was determined by gene ontology analysis. Spots common to both T. spiralis and T. britovi, spots with different expressions between the two and spots specific to each species were labelled with different cyanine dyes. In total, 196 protein spots were found in both proteomes; of these 165 were common, 23 expressed exclusively in T. spiralis and 8 in T. britovi. A comparative analysis of volume ratio values with Melanie software showed that among the common spots, nine demonstrated higher expression in T. spiralis, and 17 in T. britovi. LC-MS/MS analysis of 11 selected spots identified 41 proteins with potential antigenic characteristics: 26 were specific for T. spiralis, six for T. britovi, and eight were found in both proteomes. Gene Ontology analysis showed that the identified T. spiralis proteins possess hydrolytic endopeptidase, endonuclease and transferase activities. Similarly, most of the T. britovi proteins possess catalytic activities, such as lyase, hydrolase, isomerase and peptidase activity. The applied 2D DIGE technique visualized Trichinella spp. protein spots with different molecular weights or isoelectric point values, as well as those with different expression levels. The identified immunoreactive proteins participate in multiple processes associated with host muscle cell invasion and larval adaptation to the host environment. Their reactivity with the host immune system makes them possible candidates for the development of a novel trichinellosis diagnostic test or vaccine against helminthiasis caused by T. spiralis or T. britovi.
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