Development of a recombinant protein-based enzyme-linked immunosorbent assay and its applications in field surveillance of rodent mice for presence of immunoglobulin G against Orientia tsutsugamushi.
A recombinant protein containing the immunodominant conserved epitope region of the 56-kDa outer membrane protein of the Karp strain of Orientia tsutsugamushi was purified to near homogeneity using recombinant DNA techniques. The purified protein was used to immunize rabbits and produced an antibody that could recognize different strains of O. tsutsugamushi, as demonstrated both by Western blotting and immunofluorescence assay. An enzyme-linked immunosorbent assay (ELISA) based on this recombinant protein was developed to detect antibody (immunoglobulin G [IgG]) against O. tsutsugamushi in mice captured in different districts of Taiwan during 2000 to 2001. A significant difference was found in the antibody seroprevalence rates of Suncus murinus mice captured in different districts of Taiwan (chi(2)(4, 0.95) = 26.64; P < 0.05). Furthermore, a significant difference of IgG seropositivity rates was observed among different kinds of mice (chi(2)(5, 0.95) = 93.85; P < 0.05). Antibody seropositivity rates were higher in Bandicota indica (100%), Rattus flavipectus (96.17%), and Rattus losea (95.83%) than in Rattus norvegicus (86.05%) and Rattus mindanensis (83.67%) (chi(2)(diff, 5, 0.95) = 12.59, P < 0.05). The lowest antibody seropositivity rate (54.4%) was observed in Suncus murinus. Antibody seropositivity rates of mice from different districts differed significantly because of the significant difference in antibody seroprevalence rates for S. murinus. The results of this study indicated that the recombinant protein ELISA developed in this study could be used to conduct large-scale surveillance of rodent mice for the presence of antibody against O. tsutsugamushi. The high seroprevalence rates in rodent mice (except S. murinus) suggest that people residing in these districts are at increased risk of developing O. tsutsugamushi infection.
Wang
Yeau-Ching
YC
Institute of Preventive Medicine, National Defense Medical Center, Taipei 100, Taiwan. yeauching@ndmctsgh.edu.tw
Jian
Ting-Yu
TY
Tarn
Lih-Jeng
LJ
Hung
Yao-Wen
YW
Chao
Hai-Yuan
HY
Ji
Da-Der
DD
Liu
Hwan-Wun
HW
D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology; D003001:Cloning, Molecular; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D016056:Immunodominant Epitopes / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000097:blood*; D051379:Mice; D012285:Orientia tsutsugamushi / Q000276:immunology*; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology; D012376:Rodent Diseases / Q000175:diagnosis / Q000453:epidemiology; D012612:Scrub Typhus / Q000175:diagnosis* / Q000453:epidemiology / Q000662:veterinary; D016415:Sequence Alignment; D016036:Seroepidemiologic Studies; D013624:Taiwan
C080442:56 kDa antigen, Rickettsia; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016056:Immunodominant Epitopes; D007074:Immunoglobulin G; D011994:Recombinant Proteins