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Objective: To clone, express and purify Schistosoma japonicum fructose-1, 6-bisphosphate aldolase (SjFBPA) in E. coli and observe its expression in different developmental stages of S. japonicum., Methods: FBPA gene was amplified from S. japonicum adult worm cDNA by using PCR. The amplified product was recombined into pET28a plasmid, and inducibly expressed with IPTG in E. coli BL21. SDS-PAGE and Western blotting were employed to analyze and identify the recombinant protein SjFBPA (rSjFBPA). Then, rSjFBPA was purified by chromatographic purification and its purity was analyzed by SDS- PAGE. The protein concentration of rSjFBPA purified was measured by the BCA method. Furthermore, SjFBPA mRNA was ana- lyzed in different developmental stages of S. japonicum by RT-PCR., Results: SjFBPA was successfully amplified by using PCR and identified by restriction enzyme digestion and sequencing. The Western blotting analysis confirmed that the recombinant pro- tein could specifically reactive to the anti-His-tag monoclonal antibody. The concentration of the purified recombinant protein was about 4 mg/ml. The result of RT-PCR showed that SjFBPA mRNA was expressed in cercaria, schistosomulum, adult worm and egg of S. japonicum., Conclusion: SjFBPA is successfully recombined and expressed in a prokaryotic system, and SjFBPA mRNA is expressed in cercaria, schistosomulum, adult worm and egg of S. japonicum.

Objective: To identify the recombinant aldolase (ALD) of Plasmodium falciparum, and to develop monoclonal antibodies (McAbs) against the recombinant ALD., Methods: ALD gene was amplified by PCR from genomic DNA of FCC1/HN strain, and expressed in E. coli DH5 alpha. BALB/c mice were immunized with the recombinant ALD of P. falciparum via celiac injection for 3 times with 2 weeks interval. Three days after a booster injection, spleen cells of the immunized mice were used for producing McAbs. The immune serum was tested by IFAT and Western blotting., Results: BALB/c mice immunized with purified aldolase protein developed strong immune response to the antigen, and the titer of specific antibody reached 1:10(5) in all immune sera after the third immunization. Moreover, immune sera specifically recognized the cultured P. falciparum. Western blotting showed that the immune sera recognized specifically a Mr 41000 band of crude malaria antigen. No cross-reaction with human red cells was detected. Seven positive hybridoma cell lines were obtained after 3 rows of selection. All the McAbs' subclasses belong to IgG1. IFAT showed that only 4 McAbs could recognize the cultured P. falciparum., Conclusion: Plasmodial aldolase has been successfully expressed and purified, and the established hybridoma cell lines can secrete McAbs specific to the aldolase of P. falciparum.