Cloning, expression, and protective immunity in mice of a gene encoding the diagnostic antigen P-29 of Echinococcus granulosus.

Taeniid tapeworm Echinococcus granulosus is the causative agent of Echinococcosis, an important zoonosis with worldwide distribution. In this study, a diagnostic antigen P-29 was cloned from E. granulosus and expressed in Escherichia coli. Sequence analysis showed that EgP-29 contains 717-bp open reading frame and encodes a protein of 238 amino acid residues with a predicted molecular weight of 27.1 kDa. The recombinant EgP-29 (rEgP-29) could be recognized with antimice sera in Western blotting. The specific antibody was detected by enzyme-linked immunosorbent assay. Mice vaccinated with rEgP-29 and challenged intraperitoneally with E. granulosus protoscoleces revealed significant protective immunity of 96.6% (P<0.05), compared with the control group. Thus, rEgP-29 protein is a promising candidate for an effective vaccine to prevent secondary echinococcosis.