title: Sequence conservation of Plasmodium vivax glutamate dehydrogenase among Korean isolates and its application in seroepidemiology.
abstract: Glutamate dehydrogenase of malaria parasites (pGDH) is widely used in rapid diagnostic tests for malaria. Variation in the pGDH gene among Korean isolates of Plasmodium vivax was analysed, and a recombinant pGDH protein was evaluated for use as antigens for the serodiagnosis of vivax malaria.
  
  
  
  Genomic DNA was purified from blood samples of 20 patients and the pGDH gene of P. vivax was sequenced. Recombinant protein was prepared to determine the antigenicity of pGDH by enzyme-linked immunosorbent assay (ELISA).
  
  
  
  Partial sequence analysis of the P. vivax pGDH gene from the 20 Korean isolates showed that an open reading frame (ORF) of 1410 nucleotides encoded a deduced protein of 470 amino acids. The amino acid and nucleotide sequences were conserved among all the Korean isolates. This ORF showed 100% homology with P. vivax strain Sal-I (GenBank accession No. XP_001616617.1). The full ORF (amino acids 39-503), excluding the region before the intron, was cloned from isolate P. vivax Bucheon 3 (KJ726751) and subcloned into the expression vector pET28b for transformation into Escherichia coli BL21(DE3)pLysS. The expressed recombinant protein had a molecular mass of approximately 55 kDa and showed 84.8% sensitivity (39/46 cases) and 97.2% specificity (35/36 cases) in an ELISA. The efficacy of recombinant pGDH protein in seroepidemiological studies was also evaluated by ELISA using serum samples collected from 876 inhabitants of Gyodong-myeon, Ganghwa County, Incheon Metropolitan City. Of these samples, 91 (10.39%) showed a positive reaction with recombinant pGDH protein. Among the antibody-positive individuals, 13 (14.29%) had experienced malaria infection during the last 10 years.
  
  
  
  The pGDH genes of P. vivax isolates from representative epidemic-prone areas of South Korea are highly conserved. Therefore, pGDH is expected to be a useful antigen in seroepidemiological studies. It was difficult to identify the foci of malaria transmission in Gyodong-myeon based on the patient distribution because of the very low parasitaemia of Korean vivax malaria. However, seroepidemiology with recombinant pGDH protein easily identified regions with the highest incidence of malaria within the study area. Therefore, recombinant pGDH protein may have a useful role in serodiagnosis.
authors.affiliation: Department of Tropical Medicine and Parasitology, Inha University School of Medicine, Incheon, 22212, South Korea.
authors.forename: Bomin
authors.initials: B
authors.lastname: Seol
authors.affiliation: Division of Malaria and Parasitic Diseases, National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, 363-951, South Korea.
authors.forename: Hyun-Il
authors.initials: HI
authors.lastname: Shin
authors.affiliation: Division of Malaria and Parasitic Diseases, National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, 363-951, South Korea.
authors.forename: Jung-Yeon
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Biomedical Laboratory Science, School of Public Health, College of Health Sciences, Yonsei University, Wonju, 26493, South Korea.
authors.forename: Bo-Young
authors.initials: BY
authors.lastname: Jeon
authors.affiliation: Department of Biomedical Science, Jungwon University, Goesan, Chungbuk, 367-805, South Korea.
authors.forename: Yoon-Joong
authors.initials: YJ
authors.lastname: Kang
authors.affiliation: Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine and Asan Institute for Life Sciences, Seoul, 05505, South Korea.
authors.forename: Jhang-Ho
authors.initials: JH
authors.lastname: Pak
authors.affiliation: Department of Tropical Medicine and Parasitology, Inha University School of Medicine, Incheon, 22212, South Korea. tongsookim@inha.ac.kr.
authors.forename: Tong-Soo
authors.initials: TS
authors.lastname: Kim
authors.affiliation: Department of Biomedical Laboratory Science, School of Public Health, College of Health Sciences, Yonsei University, Wonju, 26493, South Korea. rainlee67@naver.com.
authors.forename: Hyeong-Woo
authors.initials: HW
authors.lastname: Lee
mesh_terms: D017124:Conserved Sequence; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004926:Escherichia coli; D014644:Genetic Variation; D005969:Glutamate Dehydrogenase / Q000235:genetics*; D006801:Humans; D016780:Malaria, Vivax / Q000175:diagnosis*; D010966:Plasmodium vivax / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D056910:Republic of Korea; D017422:Sequence Analysis, DNA; D012698:Serologic Tests / Q000379:methods*
chemical_list: D016054:DNA, Protozoan; D011994:Recombinant Proteins; D005969:Glutamate Dehydrogenase