Abstract: 　Objective To construct a chimeric protein of Plasmodium falciparum pre erythrocyte stage (named as PfCP 4). Methods Thrombospondin related anonymous protein (TRAP) and circumsporozoite protein (CSP) of Plasmodium falciparum have been considered important candidates for pre erythrocytic malaria vaccine. The sequences of ectodomain of TRAP (aa: 26-330) and (NANP) 19 repeat region and entire carboxy terminus of CSP were fused to generate the PfCP 4 via a hinge consisting of Gly Pro Gly. The 1577 bp sequence of PfCP 4 was synthesized by asymmetric PCR based method and the synthetic gene was inserted into pQE. The resulting plasmid was transformed into E. coli SG13009 for inducible expression with IPTG. The expression product was detected by Western blotting. Results The result of Western blotting showed that the entire PfCP 4 recombinant protein was produced under IPTG induction whereas no product was detected in the cell without induction. The molecule weight of the protein was 57 kDa which was identical to the expected size, and the product was recognized by polyclonal antibodies against CSP protein. Conclusion A chimeric protein of Plasmodium falciparum pre erythrocyte stage (named as PfCP 4) was constructed successfully.

Key words: Plasmodium falciparum, chimeric protein, CSP, TRAP, gene expression