[Identification, Expression and Antigenicity Analysis of Serpin B6 of Taenia solium].

Objective: To identify and express serpin B6 of Taenia solium (Tsserpin B6) and explore its possible use as a diagnostic antigen.

Methods: Primers for Tsserpin B6 were designed according to T. solium genome and transcriptome data. The Tsserpin B6 gene was amplified from the total RNA of T. solium cysticercus and subsequently analyzed by bioinformatics. Multiple amino acid sequence alignments of Tsserpin B6 and other parasites serpins were created using the Clustal X1.83. Phylogenetic analyses were performed using the MEGA 6.0. The recombinant expression vector pET-30a-Tsserpin B6 was constructed and expressed in E. coli strain BL21 （DE3）. The expressed proteins were purified, isolated by SDS-PAGE, and analyzed by Western blotting using pig serum infected with T. solium cysticerci.

Results: The complete reading frame of Tsserpin B6 was 1 131 bp and encoded a protein of 376 amino acids. The encoded protein had a conservative reactive center loop and distinctive domains of NEEGAE and FTVDHPFLF, and harbored 9 potential linear B cell epitopes. The expressed products of Tsserpin B6 mainly existed as an inclusion body, and reacted with pig serum infected with T. solium, resulting in a specific band at the Mr 53 000.

Conclusion: The Tsserpin B6 gene was successfully cloned, and its expressed products can be recognized by pig serum infected with T. solium.