Induction of humoral immune response against PfMSP-119 and PvMSP-119 using gold nanoparticles along with alum

The C-terminal 19 kDa fragment of merozoite surface protein 1(MSP-119) is an important vaccine candidate but a poor immunogen with available human compatible adjuvants like alum. We have investigated if Gold Nanoparticles (GNPs) based delivery system would enhance immune response to recombinant PfMSP-119 and PvMSP-119. We found that PfMSP-119/PvMSP-119 coated on GNPs or in alum was poorly immunogenic in mice, a robust antibody response was observed when PfMSP-119/PvMSP-119 coated GNPs were formulated with alum. PfMSP-119/PvMSP-119 coated GNPs strongly recognized conformation specific monoclonal antibodies showing that capping on to GNPs did not compromise with conformational integrity of these antigens, which is critical for the generation of functional antibody response. Anti-PfMSP-119 antibodies raised with GNP-alum formulation recognized the native protein on parasite surface and showed invasion inhibition of Plasmodium falciparum parasite in an in vitro assay. Antigen coated GNPs with alum may be useful in the development of an alternate adjuvant formulation.