Identification of a novel merozoite surface antigen of Plasmodium vivax, PvMSA180

• Published in: Malaria Journal
• Main Authors: Fauzi Muh, Jin-Hee Han, Myat Htut Nyunt, Seong-Kyun Lee, Hye-Yoon Jeon, Kwon-Soo Ha, Won Sun Park, Seok-Ho Hong, Md Atique Ahmed, Sunghun Na, Eizo Takashima, Takafumi Tsuboi, Eun-Taek Han
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2017
• Subjects: Plasmodium vivax; MSA180; Humoral immune response; Merozoite surface protein; Haplotype; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-017-1760-9; https://doaj.org/article/9d1ebc5e802c4a87aa0d26494b9efb48

Abstract Background Although a number of Plasmodium vivax proteins have been identified, few have been investigated as potential vaccine candidates. This study characterized the Plasmodium vivax merozoite surface antigen 180 (PvMSA180, PVX_094920), a novel P. vivax antigenic protein. Methods The target gene was amplified as four overlapping domains (D1, D2, D3 and D4) to enable expression of the recombinant protein using cell-free and bacterial expression systems. The recombinant PvMSA180 proteins were used in protein microarrays to evaluate the humoral immune response of 72 vivax-infected patients and 24 vivax-naïve individuals. Antibodies produced in mice against the PvMSA180-D1 and -D4 domains were used to assess the subcellular localization of schizont-stage parasites with immunofluorescence assays. A total of 51 pvmsa180 sequences from 12 countries (41 sequences from PlasmoDB and 6 generated in this study) were used to determine the genetic diversity and genealogical relationships with DNAsp and NETWORK software packages, respectively. Results PvMSA180 consists of 1603 amino acids with a predicted molecular mass of 182 kDa, and has a signal peptide at the amino-terminus. A total of 70.8% of patients (51/72) showed a specific antibody response to at least one of the PvMSA180 domains, and 20.8% (15/72) exhibited a robust antibody response to at least three of the domains. These findings suggest that PvMSA180 is targeted by the humoral immune response during natural infection with P. vivax. Immunofluorescence analysis demonstrated that PvMSA180 is localized on the merozoite surface of schizont-stage parasites, and pvmsa180 sequences originating from various geographic regions worldwide showed low genetic diversity. Twenty-two haplotypes were found, and haplotype 6 (Hap_6, 77%) of pvmsa180 was detected in isolates from six countries. Conclusions A novel P. vivax surface protein, PvMSA180, was characterized in this study. Most of P. vivax-infected patients had specific antibodies against particular antigenic ...