Abstract: 　Objective To screen and identify the recombinants from the cDNA library of the adult Paragonimus west-ermani (PwA) for immunodiagnosis and immunoprophylaxis. Methods PwA cDNA library was screened with the PwA antigen immunized rabbit sera(IRS) pre-absorbed by the extract of E. coli XLl-Blue. The recombinants from positive clones were amplified by PCR, sequenced and cut off by KpnI/BarnHI and, then sub-cloned into pRESETB vector. The fusion protein was expressed,analysed by SDS-PAGE and identified by Western blotting with immune rabbit serum against worm antigen of Paragonimus westerrnani. Results The inserted cDNA fragment from the positive clone Pw-2 was about 800 bp, which contained an open reading frame(ORF) encoding Pw pre-procathepsin L belonging to cysteinase family. Expression product of Pw-2 was a fusion protein of 32 kDa, which can be recognized by immune rabbit serum against worm antigen of Paragonimus 晈esterrnani. Conclusion A recombinant plasmid Pw-2 encodes Pw pre-procathepsin L is constructed.

Key words: Paragonimus westermani, cDNA library, recombinant protein