A recombinant 19 kDa Plasmodium berghei merozoite surface protein 1 formulated with alum induces protective immune response in mice.

We investigated the immunogenicity of recombinant rMSP1 (rPbMSP1) that was generated from Plasmodium berghei. The rPbMSP1 formulated in alum was found to be immunogenic which induced high levels of specific anti-rPbMSP1 antibody. The IgG2a response predominated over IgG1 during the challenge infection in the vaccinated mice. Mice vaccinated with rPbMSP1 in alum mounted significant protective immunity against challenge infection (P < 0.01). On day 121 after the booster, three out of ten mice immunized with rPbMSP1 in PBS survived parasite infection (P < 0.05) and eight out of ten mice vaccinated with r MSP1 in alum did (P < 0.01). Hence, immunization with MSP1 in alum obviously has conferred protective effects, which prevented death from P. berghei lethal infection in mice (P < 0.01). These observations provide an excellent model for clinical assessment of this formulation in human subjects.