[Establishment and evaluation of colloid gold labeled immunochromatographic strip test for rapid diagnosis of alveolar echinococcosis].
OBJECTIVE
To establish and evaluate a colloid gold immunochromatographic strip test for the diagnosis of alveolar echinococcosis.


METHODS
Total RNA was prepared from Echinococcus multilocularis protoscoleces collected from Xinjiang Uygur Autonomous Region. Em18 gene was obtained by reverse transcription-polymerase chain reaction (RT-PCR). The PCR product was sequenced and cloned into pGEX-3X vector. The recombinant plasmid was expressed and induced by isopropyl-beta-D-thiogalactopyranoside (IPTG) to obtain recombinant protein. The anti-human IgG monoclonal antibodies was conjugated with colloid gold as detecting reagent; the recombinant Em18 antigen and goat anti-mouse IgG were immobilized on nitrocellulose in proper position. The prepared immunochromatographic strip was evaluated using serum samples from patients with alveolar echinococcosis (56), cystic echinococcosis (87), cysticercosis (30), schistosomiasis japonica (10), toxoplasmosis (10) and healthy subjects (50) . Comparison between the immunochromatographic strip test and ELISA was made by kappa statistics.


RESULTS
Sensitivity detected by the immunochromatographic strip test was 92.9% (52/56). The cross-reactivity to cystic echinococcosis and cysticercosis was 9.2% (8/87) and 3.3% (1/30), respectively. There was no cross reactivity with schistosomiasis japonica and toxoplasmosis. 4 samples out of 50 healthy people showed false positive reaction. The overall specificity was 93.0 (174/187). Sensitivity and specificity both showed no statistical difference between immunochromatographic strip test and ELISA. High degree of agreement was observed between the strip test and ELISA (kappa = 0.98).


CONCLUSIONS
The developed immunochromatographic strip test using recombinant Em18 antigen as coated antigen is a sensitive, specific, simple and rapid assay for diagnosing alveolar echinococcosis.
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, China.
Chun-Hua
CH
Gao
Feng
F
Shi
Jun-Yun
JY
Wang
Yue-Tao
YT
Yang
Hui-Hui
HH
Zhu
D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D002846:Chromatography, Affinity / Q000379:methods*; D004443:Echinococcosis; D004444:Echinococcosis, Hepatic / Q000175:diagnosis* / Q000469:parasitology; D048210:Echinococcus multilocularis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D017979:Gold Colloid; D006801:Humans; D012680:Sensitivity and Specificity
D000947:Antigens, Helminth; C117889:Em18 antigen; D017979:Gold Colloid