Antibodies against a Plasmodium falciparum RON12 inhibit merozoite invasion into erythrocytes

Publication date: Available online 17 October 2018Source: Parasitology InternationalAuthor(s): Daisuke Ito, Eizo Takashima, Tsutomu Yamasaki, Shinya Hatano, Tomoyuki Hasegawa, Kazutoyo Miura, Masayuki Morita, Amporn Thongkukiatkul, Mahamadou Diakite, Carole A. Long, Jetsumon Sattabongkot, Rachanee Udomsangpetch, Hideyuki Iriko, Tomoko Ishino, Takafumi TsuboiAbstractProteins coating Plasmodium merozoite surface and secreted from its apical organelles are considered as promising vaccine candidates for blood-stage malaria. The rhoptry neck protein 12 of Plasmodium falciparum (PfRON12) was recently reported as a protein specifically expressed in schizonts and localized to the rhoptry neck of merozoites. Here, we assessed its potential as a vaccine candidate. We expressed a recombinant PfRON12 protein by a wheat germ cell-free system to obtain anti-PfRON12 antibody. Immunoblot analysis of schizont lysates detected a single band at approximately 40 kDa under reducing conditions, consistent with the predicted molecular weight. Additionally, anti-PfRON12 antibody recognized a single band around 80 kDa under non-reducing conditions, suggesting native PfRON12 forms a disulfide-bond-mediated multimer. Immunofluorescence assay and immunoelectron microscopy revealed that PfRON12 localized to the rhoptry neck of merozoites in schizonts and to the surface of free merozoites. The biological activity of anti-PfRON12 antibody was tested by in vitro growth inhibition assay (GIA), and the ra...
Source: Parasitology International - Category: Parasitology Source Type: research