title: Expression of recombinant proteins of Orientia tsutsugamushi and their applications in the serodiagnosis of scrub typhus.
abstract: In this study, recombinant proteins that encompassed the AD I-AD III regions of 56 kDa immunodominant gene of 2 Orientia tsutsugamushi (OT) serotypes; Gilliam and TA763 were expressed in Escherichia coli. Both recombinant proteins exhibited serologic cross-reactivity with the rabbit antisera against various OT serotypes, as evaluated by enzyme-linked immunosorbent assay (ELISA), but not against other rickettsial species, including Rickettsia typhi, R. prowazekii and TT118 SFG rickettsiae. The feasibility of using the recombinant proteins as a diagnostic reagent was further evaluated by ELISA using sera from blood donors and scrub typhus patients. The results suggested a higher affinity of the antihuman IgM than IgG with both recombinant proteins. The IgM ELISA findings were agreeable with the results of indirect immunoperoxidase (IIP) assay especially with sera of high antibody (1:1600). However, more than one antigen are probably needed for development of an effective assay for serodiagnosis of scrub typhus in endemic areas.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: S T
authors.initials: ST
authors.lastname: Tay
authors.forename: M Y
authors.initials: MY
authors.lastname: Rohani
authors.forename: T M
authors.initials: TM
authors.lastname: Ho
authors.forename: S
authors.initials: S
authors.lastname: Devi
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis*; D001483:Base Sequence; D003429:Cross Reactions; D004269:DNA, Bacterial / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D008969:Molecular Sequence Data; D012285:Orientia tsutsugamushi / Q000276:immunology*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011817:Rabbits; D011994:Recombinant Proteins / Q000032:analysis* / Q000494:pharmacology; D012612:Scrub Typhus / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D011994:Recombinant Proteins