AUTHOR=Wang Zhong Q. , Liu Ruo D. , Sun Ge G. , Song Yan Y. , Jiang Peng , Zhang Xi , Cui Jing 

TITLE=Proteomic Analysis of Trichinella spiralis Adult Worm Excretory-Secretory Proteins Recognized by Sera of Patients with Early Trichinellosis

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00986

DOI=10.3389/fmicb.2017.00986

ISSN=1664-302X

ABSTRACT=<p>The most commonly used serodiagnostic antigens for trichinellosis are the excretory-secretory (ES) antigens from <italic>T. spiralis</italic> muscle larvae (ML), but the specific antibodies against the ML ES antigens are usually negative during early stage of <italic>Trichinella</italic> infection. The recent studies demonstrated that <italic>T. spiralis</italic> adult worm (AW) antigens were recognized by mouse or swine infection sera on Western blot as early as 7–15 days post-infection (dpi), the AW antigens might contain the early diagnostic markers for trichinellosis. The purpose of this study was to screen early diagnostic antigens in <italic>T. spiralis</italic> AW ES proteins recognized by sera of early patients with trichinellosis. <italic>T. spiralis</italic> AW were collected at 72 h post-infection (hpi), and their ES antigens were analyzed by SDS-PAGE and Western blot. Our results showed that 5 protein bands (55, 48–50, 45, 44, and 36 kDa) were recognized by sera of early patients with trichinellosis collected at 19 dpi, and were subjected to shotgun LC–MS/MS and bioinformatics analyses. A total of 185 proteins were identified from <italic>T. spiralis</italic> protein database, of which 116 (67.2%) proteins had molecular weights of 30∼60 kDa, and 125 (67.6%) proteins with pI 4–7. Bioinformatic analyses showed that the identified proteins have a wide diversity of biological functions (binding of nucleotides, proteins, ions, carbohydrates, and lipids; hydrolase, transferase, and oxidoreductase, etc.). Several enzymes (e.g., adult-specific DNase II, serine protease and serine protease inhibitor) could be the invasion-related proteins and early diagnostic markers for trichinellosis. Moreover, recombinant <italic>T. spiralis</italic> serine protease (rTsSP-ZH68) was expressed in <italic>E. coli</italic> and its antigenicity was analyzed by Western blot with the early infection sera. The rTsSP-ZH68 was recognized by sera of infected mice at 8–10 dpi and sera of early patients with trichinellosis at 19 dpi. <italic>T. spiralis</italic> AW proteins identified in this study, especially serine protease, are the promising early diagnostic antigens and vaccine candidates for trichinellosis.</p>