Characterization of caveola-vesicle complexes (CVCs) protein, PHIST/CVC-81₉₅ in Plasmodium vivax

Plasmodium vivax produces numerous caveola-vesicle complex (CVC) structures beneath the membrane of infected erythrocytes. Recently, a member helical interspersed subtelomeric (PHIST) superfamily protein, PcyPHIST/CVC-81₉₅, was identified as CVCs-associated protein in Plasmodium cynomolgi and essential for survival of this parasite. Very little information has been documented to date about PHIST/CVC-81₉₅ protein in P. vivax. In this study, the recombinant PvPHIST/CVC-81₉₅ N and C termini were expressed, and immunoreactivity was assessed using confirmed vivax malaria patients sera by protein microarray. The subcellular localization of PvPHIST/CVC-81₉₅ N and C termini in blood stage parasites was also determined. The antigenicity of recombinant PvPHIST/CVC-81₉₅ N and C terminal proteins were analyzed by using serum samples from the Republic of Korea. The results showed that immunoreactivities to these proteins had 61% and 43% sensitivity and 96.9% and 93.8% specificity, respectively. The N terminal of PvPHIST/CVC-81₉₅ which contains transmembrane domain and export motif (PEXEL; RxLxE/Q/D) produced CVCs location throughout the erythrocytic-stage parasites. However, no fluorescence was detected with antibodies against C terminal fragment of PvPHIST/ CVC-81₉₅. These results suggest that the PvPHIST/CVC-81₉₅ is localized on the CVCs and may be immunogenic in natural infection of P. vivax.