title: Improvement of the diagnostic sensitivity of scrub typhus using a mixture of recombinant antigens derived from Orientia tsutsugamushi serotypes.
abstract: Diagnosis of scrub typhus is difficult because its symptoms are very similar to other acute febrile illnesses, such as leptospirosis, murine typhus, and other viral hemorrhagic fevers. To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We have developed a chimeric recombinant antigen cr56 and two other recombinant antigens, r21 and kr56, from various serotypes of Orientia tsutsugamushi. They were tested for the detection of antibodies against O. tsutsugamushi in the patient's serum samples using enzyme-linked immunosorbent assay (ELISA) and dot-blot analyses. As of conventional immunofluorescence assay (IFA), when the mixture of these three recombinant antigens was used, both sensitivity and specificity of the recombinant antigens were increased up to 98% in IgM and IgG at ELISA and dot blotting. Additionally, both sensitivity and specificity by detection of IgM and IgG antibodies at rapid diagnostic test (RDT), using the mixture of three antigens and gold conjugated antibodies, were 99%. Our results suggest the use of mixture of these recombinant antigen proteins in ELISA or RDT is suitable as a diagnostic test for scrub typhus.
authors.affiliation: Immunemed, Chuncheon, Korea.
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Seon-Ju
authors.initials: SJ
authors.lastname: Yeo
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Ye-Ju
authors.initials: YJ
authors.lastname: Woo
authors.forename: Min-Woo
authors.initials: MW
authors.lastname: Kim
authors.forename: Seung-Han
authors.initials: SH
authors.lastname: Kim
authors.forename: In-Ae
authors.initials: IA
authors.lastname: Chang
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Jeon
authors.forename: Byung-Jae
authors.initials: BJ
authors.lastname: Park
authors.forename: Gi-Jun
authors.initials: GJ
authors.lastname: Song
authors.forename: Myoung-Gu
authors.initials: MG
authors.lastname: Lee
authors.forename: Ik-Sang
authors.initials: IS
authors.lastname: Kim
authors.forename: Yoon-Won
authors.initials: YW
authors.lastname: Kim
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood / Q000737:chemistry / Q000276:immunology; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D012285:Orientia tsutsugamushi / Q000276:immunology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012612:Scrub Typhus / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D012703:Serotyping
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011994:Recombinant Proteins; D006046:Gold
keywords: ELISA; IFA; Orientia tsutsugamushi; RDT; Recombinant Antigen; Scrub Typhus