Abstract
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 1.99×102 TCID50/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. J. Clin. Lab. Anal. 19:150–159, 2005. © 2005 Wiley‐Liss, Inc.
Keywords: rapid immunochromatographic test (RICT), severe acute respiratory syndrome‐associated coronavirus (SARS‐CoV), nucleocapsid antigen (N‐Ag)
| Abbreviations | |
|---|---|
| SARS | severe acute respiratory syndrome |
| SARS‐CoV | SARS‐associated coronavirus |
| RICT | rapid immunochromatographic test |
| EIA | enzyme immunoassay |
| N‐Ag | nucleocapsid antigen |
| MoAb | monoclonal antibody |
| TCID50 | 50 tissue culture infective dose virus |
| WB | Western blotting |
| SDS‐PAGE | sodium dodecyl sulfate‐polyacrylamide gel electrophoresis |
| POD | peroxidase |
| BSA | bovine serum albumin |
| ALP | alkaline phosphatase |
| NP‐40 | Nonidet‐P40 |
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