Abstract: To construct a recombinant plasmid contain CP15 gene of Cryptosporidium parvum(C.parvum) and obtain recombinant protein. The surface antigen CP15 gene fragment of C.parvum was amplified from plasmid pMD-CP15 by PCR,and subcloned into pGEX 4T-3.The fusion express recombinant vector pGEX-CP15 was constructed in E.coli BL21. The recombinant protein was induced by 1 mmol/L IPTG and identified by SDS-PAGE and Western blotting. The CP15 gene fragment was amplified correctly as the size of gene was about 390 bp, and the recombinant plasmid pGEX-CP15 was constructed. The protein band with a molecular weight of 42 ku was detected on SDS-PAGE, which totally same with the theoretical size. The expressed protein was identified by Western blotting performed with GST serum. The fusion protein of CP15 was highly expressed in E.coli.

Key words: Cryptosporidium parvum; CP15 gene; prokaryotic expression; identify