Ficolin-A Enhances Inhibition of the C-Terminal 19 kDa Region of Merozoite Surface Protein-1 of Plasmodium berghei Using Test In Vivo

BACKGROUND: Malaria remains a serious public health problem with significant morbidity and mortality. This study was conducted to identify whether ficolin-A could play an active role of against malaria infection. METHODS: The function of ficolin-A was analyzed in mouse model. The open reading frame of ficolin-A was cloned from the liver of new born C57BL/6 mice by RT-PCR and then inserted into the expression vector of eukaryon to construct pVAX1-ficolin-A plasmid. Meanwhile, the open reading frame of the 19-kDa fragment of merozoite surface protein-1 of Plasmodium berghei (MSP1(19)) was cloned and then the expression vector of eukaryon, pVAX1- MSP1(19) was constructed. Both recombinant vectors were used in the mouse model of infection by Plasmodium berghei. RESULTS: pVAX1-ficolin-A alone could not significantly suppress parasite density and prolong survival time of infection mice; however, when injected pVAX1-ficolin-A and pVAX1-MSP1(19) together, the percent of invasion by Plasmodium was decreased (from 43.78% to 22.23% at 10 day after infection, compared to vector) and the survival time was prolonged significantly in the infection mouse model (P=0.01). CONCLUSION: Ficolin-A can enhance the immunoprotection of MSP1(19), it implies ficolin-A may be used as immunoenhancer in the study of vaccine defending malaria.