title: Genetic variation of aldolase from Korean isolates of Plasmodium vivax and its usefulness in serodiagnosis.
abstract: BACKGROUND
  The malaria aldolase is widely used as rapid diagnostic test (RDT), but the efficacy in aspect of its serological effectiveness in diagnosis is not known. The genetic variation of Korean isolates was analysed and recombinant aldolase was evaluated as a serological antigen in Plasmodium vivax malaria.
  
  
  METHODS
  Genomic DNA was purified and the aldolase gene of P. vivax from 25 patients' blood samples was amplified. The samples came from 5 epidemic areas; Bucheon-si, Gimpo-si, Paju-si of Gyeonggido, Gangwha-gun of Incheon metropolitan city, and Cheorwon of Gangwon-do, South Korea. The antigenicity of the recombinant aldolase was tested by western blot and enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Sequence analysis of 25 Korean isolates of P. vivax showed that the open reading frame (ORF) of 1,110 nucleotides encoded a deduced protein of 369 amino acids (aa). This ORF showed 100% homology with the P. vivax Sal I strain (XM_00165894) and P. vivax WDK strain (AF247063), 87.4% homology with Plasmodium falciparum (AF179421), 90.6% homology with Plasmodium chabaudi (AF247060), 89.5% homology with Plasmodium vinckei (AF247061), and 96.7% homology with Plasmodium knowlesi. A single nucleotide polymorphism (SNP) at nucleotide 180 (G to A, n = 5) was also observed in the isolates. The expressed recombinant protein had a molecular weight of approximately 31 kDa (monomeric form) and 62 kDa (dimeric form) as analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Among 109 P. vivax patients, 32 (29.4%) had positive in an enzyme-linked absorbance assay (ELISA). This result showed significant correlation between ELISA and an indirect fluorescent antibody test (IFAT) (P < 0.0001).
  
  
  CONCLUSIONS
  The aldolase gene from Korean isolates of P. vivax showed one SNP at nucleotide position 180; this SNP mutant was discovered in only the western part of Han River, and included the regions of Ganghwa, Gimpo, and Bucheon. Based on the results, the relationship between antibody production against aldolase and the pattern of disease onset should be more investigated before using aldolase for serodiagnosis.
authors.affiliation: Division of Malaria and Parasitic Diseases, National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon-gun 363-951, Republic of Korea.
authors.forename: Jung-Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Hyung-Hwan
authors.initials: HH
authors.lastname: Kim
authors.forename: Hyun-ll
authors.initials: HL
authors.lastname: Shin
authors.forename: Youngjoo
authors.initials: Y
authors.lastname: Sohn
authors.forename: Hyuck
authors.initials: H
authors.lastname: Kim
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Lee
authors.forename: Won-Ja
authors.initials: WJ
authors.lastname: Lee
authors.forename: Hyeong-Woo
authors.initials: HW
authors.lastname: Lee
mesh_terms: D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D015153:Blotting, Western / Q000379:methods; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D014644:Genetic Variation; D006805:Human Experimentation; D006801:Humans; D016780:Malaria, Vivax / Q000175:diagnosis*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010966:Plasmodium vivax / Q000201:enzymology* / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D056910:Republic of Korea; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012698:Serologic Tests / Q000379:methods
chemical_list: D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D011994:Recombinant Proteins; D005634:Fructose-Bisphosphate Aldolase