title: Performance of coumarin-derived dendrimer-based fluorescence-linked immunosorbent assay (FLISA) to detect malaria antigen.
abstract: BACKGROUND
  Due to limitation of conventional malaria diagnostics, including microscopy, polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA), alternative accurate diagnostics have been demanded for improvement of sensitivity and specificity.
  
  
  METHODS
  Serially diluted Plasmodium LDH antigens, Plasmodium falciparum-infected human red blood cells (RBC) derived from in vitro culture or patient's samples were used for evaluation of the performance of fluorescence-linked immunosorbent assay (FLISA). Microscopic examination was used to determine parasite density and the performance of FLISA was compared to ELISA. Finally, sensitivity and specificity of FLISA was determined by human specimens infected with P. falciparum, Plasmodium vivax, Toxoplasma gondii, and amoebae.
  
  
  RESULTS
  As a result of FLISA, the fluorescent intensity was highly correlated with antigen amount and FLISA was more sensitive than ELISA. FLISA detected at least 0.01 ng/ml of pLDH antigen, which showed 1,000-fold higher sensitivity than ELISA. In vitro-cultured P. falciparum was detected up to 20 parasite number/μL in FLISA but 5120 parasite number/μLin sandwich ELISA. In vitro P. falciparum-infected RBC number was highly correlated with fluorescent intensity (R2 = 0.979), showing that FLISA was reliable for detection of P. falciparum and available for quantification of parasite numbers. Furthermore, eighteen patient samples infected with P. falciparum (n = 9) and P. vivax (n = 9) showed 100% of sensitivity (18/18). FLISA showed 96.3% of specificity (26/27) because one sample of patient blood infected with T. gondii gave a false positive reactivity among healthy donors (n = 9), T. gondii-infected patients (n = 9), and amoeba-infected patients (n = 9).
  
  
  CONCLUSIONS
  FLISA has a keen and high performance to detect malaria antigen, suggesting a potential assay as malaria immunodiagnostic.
authors.forename: Seon-Ju
authors.initials: SJ
authors.lastname: Yeo
authors.forename: Dinh Thi
authors.initials: DT
authors.lastname: Huong
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Han
authors.forename: Jung-Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Won-Ja
authors.initials: WJ
authors.lastname: Lee
authors.forename: Ho-Joon
authors.initials: HJ
authors.lastname: Shin
authors.affiliation: Zoonosis Research Center, Department of Infection Biology, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea. ethan@kangwon.ac.kr.
authors.forename: Eun-Taek
authors.initials: ET
authors.lastname: Han
authors.forename: Hyun
authors.initials: H
authors.lastname: Park
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D003374:Coumarins; D050091:Dendrimers; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D004912:Erythrocytes / Q000469:parasitology*; D019085:Fluorescent Antibody Technique, Direct / Q000379:methods*; D005456:Fluorescent Dyes; D005470:Fluorometry; D006801:Humans; D007124:Immunoenzyme Techniques; D007163:Immunosorbent Techniques; D007770:L-Lactate Dehydrogenase / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D016778:Malaria, Falciparum / Q000097:blood* / Q000175:diagnosis / Q000469:parasitology; D016780:Malaria, Vivax / Q000097:blood* / Q000175:diagnosis / Q000469:parasitology; D008969:Molecular Sequence Data; D018512:Parasitemia / Q000097:blood* / Q000175:diagnosis / Q000469:parasitology; D010961:Plasmodium / Q000201:enzymology; D010963:Plasmodium falciparum / Q000276:immunology* / Q000302:isolation & purification; D010966:Plasmodium vivax / Q000276:immunology* / Q000302:isolation & purification; D015800:Protozoan Proteins / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D003374:Coumarins; D050091:Dendrimers; D000939:Epitopes; D005456:Fluorescent Dyes; D015800:Protozoan Proteins; C030123:coumarin; D007770:L-Lactate Dehydrogenase