Immunogenicity of C-terminus of Plasmodium falciparum merozoite surface protein 1 expressed as a non-glycosylated polypeptide in yeast

The C-terminal region of the merozoite surface protein 1 (MSP1_(19)) is one of the most promising vaccine candidates against the erythrocytic forms of malaria.In the present study,a gene encoding Plasmodium falciparum MSP1_(19) was expressed in yeast Pichia pastoris.A non-glycosylated form of the recombinant protein MSP1_(19) was purified from culture medium.This recombinant protein maintains its antigenicity.Significant immune responses were seen in C57BL/6 mice after the second immunization. Moreover,the specific antibodies recognized the native antigens of P.falciparum,The prevailing isotypes of immunoglobulin (Ig)G associated with immunization were IgG1,IgG2a and IgG2b.The antibodies isolated from mouse sera immunized with MSP1_(19) can inhibit parasite growth in vitro.Based on these immunological studies,we concluded that MSP1_(19) deserves further evaluation in pre-clinical immunizations against P.falciparum.