Figure 2

The specificity of the developed ELISAs. (a) Sequence homology analysis of SARS-CoV-2 N protein and S1 subunit compared to other human coronaviruses. (b) Developed ELISAs were tested for their specificity using sera known to be seronegative for SARS-CoV-2 and MERS-CoV (HC; n = 8), seropositive sera for MERS-CoV (MERS; n = 2) or seropositive sera for SARS-CoV-2 (COVID-19; n = 3). These serum samples were also tested for their reactivity in IgG and IgM ELISAs developed for MERS-CoV S1 and N proteins, as well as full S protein from hCoV-OC43, hCoV-NL63, hCoV-229E, and hCoV-HKU1 viruses. The dotted lines represent the cut-off of each assay. The cut-off values for hCoV-OC43, hCoV-NL63, hCoV-229E, and hCoV-HKU1 ELISAs were set at arbitrary value = blank mean + 3SD.