Abstract:A gene termed as 45m was isolated from the larval stage of Taenia multiceps which was similar to the 45W gene from Taenia ovis as demonstrated by PCR.This gene was successfully expressed in E.coli through the prokaryotic expression vector pET41b.The purified 45M recombinant protein was used to immunize mice.And the antiserum produced could react with the protein appearing as a 63 kDa protein band in Western blot assay,which could be isolated from cyst fluid,protoscoleces,cyst membrane and adult worms of adult Echinococcus granulosus.In addition,a gene was also isolated from adult Echinococcus multicep and this gene had 86% and 76% homologous similarities to the larval nucleotide and protein sequences respectively.Also,it had 57% homologous similarity in amino acid to the protective protein EG95 of E.granolosus.The antiserum could also recognize a protein band in Western blot assay isolated from different developmental stages of E.granolosus.These results suggest that the 45m antigen exists in different stages of E.multicep and E.granolosus and the 45M has the same epitopes in proteins of E.granulosus.