A sensitive and specific antigen detection assay for Middle East respiratory syndrome coronavirus

Chen, Yixin; Chan, Kwok-Hung; Kang, Yahong; Chen, Honglin; Luk, Hayes KH; Poon, Rosana WS; Chan, Jasper FW; Yuen, Kwok-Yung; Xia, Ningshao; Lau, Susanna KP; Woo, Patrick CY

Evaluation of MERS-CoV-NP capture ELISA NPAs from 129 patients with viral respiratory tract infections (influenza A virus (n 5 10), influenza B virus (n 5 10), influenza C virus (n 5 2), adenovirus (n 5 10), RSV (n 5 10), parainfluenza virus 1 (n 5 5), parainfluenza virus 2 (n 5 2), parainfluenza virus 3 (n 5 10), parainfluenza virus 4 (n 5 10), human rhinoviruses (n 5 30), human metapneumovirus (n 5 10), HCoV-HKU1 (n 5 5), HCoV-OC43 (n 5 5), HCoV-229E (n 5 5), and HCoV-NL63 (n 5 5)) and simulated MERS-CoV positive NPAs were used for the evaluation of the ELISA. NPAs positive for influenza C virus, parainfluenza virus 4, human rhinoviruses, human metapneumovirus, and HCoVs were determined by RT-PCR and those for the other respiratory viruses were determined by indirect immunofluorescence assay as described in our previous publications. [22] [23] [24] [25] [26] MERS-CoV culture and titration were performed as we described previously. 16 Simulated MERS-CoV positive NPAs were prepared by adding serial dilutions (1-500 000 TCID 50 /0.1 mL) of MERS-CoV to two different NPAs and 20 TCID 50 /0.1 mL and 200 TCID 50 /0.1 mL of MERS-CoV to 10 additional NPAs negative for the above mentioned respiratory viruses. The ELISA was performed as described above, using 50 mL of each NPA sample.