Abstract: Foot-and-mouth disease virus(FMDV) is an important pathogen worldwide; consequently, an important goal is the developments of diagnostic methods. To acquire an optimal diagnostic antigen allows one to distinguish vaccinated anionals from infected animals, a recombinant expression plasmid pPIC9K-3ABCt was constructed by inserting of FMDV 3ABC truncated gene(525 bp) into yeast expression vector pPIC 9K. Se-condly, plasmid pPIC9K-3ABCt was linearized by BglII, and transformed into GS115 cells by electroporation. Positive clones were selected with MD/MM plates and confirmed by PCR and RT-PCR. Finally, expression product of 3ABCt was analyzed by SDS-PAGE and Western blot. The results show that the induced recombinant Pichia pastoris GS115/pPIC9K-3ABCt could secret 3ABC protein mainly in dimer form into culture supernatant, which had good immunoreactivity and antigen specificity and its molecular weight output was about 40000. Expression of 3ABCt protein reached peek at 96 h after induction, maximum expression was accumulated up to 18% of the total supernatant protein, and production was about 23.4 mg/L.

Key words: Foot-and-mouth disease virus(FMDV), 3ABC Truncated gene, Pichia pastoris, Secretory expression, Diagnostic antigen