[Studies on immune responses in mice to expressed products from CSP gene of Plasmodium falciparum FCC1/HN isolate]

To construct the eukaryotic expression system with pcDNA3-PfCSP/HeLa for CSP gene of Plasmodium falciparum, and to observe the immune responses in BALB/c mice induced by the expressed proteins.

The recombinant plasmid pcDNA3-PfCSP was transformed into mammalian cell line of human HeLa cells. The expressed protein was isolated and analyzed by SDS-PAGE and used for immunization of BALB/c mice by subcutaneous, intravenous or intraperitoneal administration, respectively. ELISA, Western blotting, T lymphocyte proliferation test, natural killer cell activity and CD4+ and CD8+ T cells detection were used for observation of the level of humoral and cellular immune responses.

Immune sera strongly reacted with the expressed protein. The titer of the antibodies was up to 1:6,400 by ELISA. Western blotting analysis revealed a specific band at 38.3 kDa. The specific proliferative response with immunized BALB/c mice spleen cells was remarkablely higher than that with control ones. The ratio of CD4+ and CD8+ T cells and the NK cell activity were significantly higher in the immunization group than that in the control groups.

The humoral and cell-mediated immune responses and elevated NKC activity to expressed products with the eukaryotic expression system can specifically be detected in BALB/c mice to generate, indicating that the expressed protein could enhance immune activity in mice.