Objectives To construct a prokaryotic expression vector for the 43 ku excretory-secretory antigen gene of Trichinella spiralis from swine in Yunnan Province and to express the protein of interest in order to study its function.Methods Adult T.spiralis was collected from swine in Yunnan Province,and its total RNA was extracted.The 43 ku excretory-secretory antigen gene was amplified with RT-PCR and inserted into a pMD18-T vector to construct a recombinant plasmid.The recombinant plasmid was subjected to doub...