Novel rapid immunochromatographic test based on an enzyme immunoassay for detecting nucleocapsid antigen in SARS-associated coronavirus.
A novel severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been discovered. The detection of both antigens and antibodies in SARS-CoV from human specimens with suspected SARS plays an important role in preventing infection. We developed a novel rapid immunochromatographic test (RICT) based on the sandwich format enzyme immunoassay (EIA) with an all-in-one device for detecting the native nucleocapsid antigen (N-Ag) of SARS-CoV using monoclonal antibodies (MoAbs), which we produced by immunizing recombinant N-Ag to mice. RICT is a qualitative assay for respiratory aspirates and serum specimens. With this assay, a positive result can be judged subjectively by the appearance of a blue line on the device 15 min after the sample is applied. RICT with several pairs of MoAbs showed a high sensitivity for the detection of recombinant N-Ag as well as viral N-Ag of SARS-CoV. rSN122 and rSN21-2 were the best MoAbs for immobilized antibody and enzyme labeling, respectively. With regard to analytical sensitivity, RICT detected N-Ag at 31 pg/mL for recombinant N-Ag, and at 1.99 x 10(2) TCID(50)/mL for SARS-CoV. The specificity of RICT was 100% when 150 human sera and 50 nasopharyngeal aspirates (NSPs) were used. RICT based on an EIA using the rSN122/rSN21-2 pair is a sensitive, specific, and reliable rapid assay for detecting N-Ag in SARS-CoV treated with either heat or Triton X-100.
Kogaki
Hiroyuki
H
Research and Development Division, Fujirebio Inc., Tokyo, Japan.
Uchida
Yoshiaki
Y
Fujii
Nobuyuki
N
Kurano
Yoshihiro
Y
Miyake
Kazushige
K
Kido
Yasuji
Y
Kariwa
Hiroaki
H
Takashima
Ikuo
I
Tamashiro
Hiko
H
Ling
Ai-Ee
AE
Okada
Masahisa
M
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002522:Chlorocebus aethiops; D002845:Chromatography; D017934:Coronavirus / Q000276:immunology*; D004274:DNA, Recombinant; D004926:Escherichia coli; D007124:Immunoenzyme Techniques / Q000295:instrumentation / Q000379:methods*; D051379:Mice; D019251:Nucleocapsid / Q000032:analysis* / Q000276:immunology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D045169:Severe Acute Respiratory Syndrome / Q000821:virology*; D013997:Time Factors; D014709:Vero Cells
D000911:Antibodies, Monoclonal; D004274:DNA, Recombinant