Immune response in mice induced by C terminal encoding gene of Plasmodium falciparum histidine rich protein. 2

OBJECTIVE: To explore the humoral and cellular immune responses in mice to eukaryotic expression recombinant plasmid encoding histidine rich protein 2 (HRP-II) of Plasmodium falciparum. METHODS: The start and stop codes were introduced into HRP-II gene fragment, the reading frame and the position of start and stop codes in HRP-II were identified by sequencing. HRP-II fragment containing the start and stop codes was cloned into pcDNA3.1 (-) to form pcDNA3.1 (-)/HRP-II. The BALB/c mice were immunized i.m. with the plasmids for 3 times in 3 weeks intervals. Two weeks after the last immunization, the sera and splenocytes were collected to investigate anti-HRP-II antibodies by ELISA and the splenocytes proliferation response to HRP-II. RESULTS: Sequence data show that the reading frame and the position of start and stop codes are correct. Restriction enzyme digestion indicated that the HRP-II gene fragment containing start and stop codes was successfully cloned into pcDNA3.1 (-). Mice raised significant anti-HRP-II antibodies after pcDNA3.1 (-)/HRP-II immunization, and the splenocytes proliferated prominently when stimulated with HRP-II protein. CONCLUSION: Eukaryotic expression recombinant plasmid encoding HRP-II gene can induce significantly humoral and cellular immune response in mice. HRP-II gene may be a good candidate for P. falciparum blood-stage multiple DNA vaccine.