Figure 1. .

Cross-reactivity between human plasma against NL63, 229E, OC43, and HKU1 with the N protein of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). A, Western blot analysis to determine the reactivity of human plasma containing antibodies against NL63, 229E, OC43, and HKU1. Plasma samples were diluted at 1:400 and incubated with the N protein of NL63, 229E, OC43 HKU1, and SARS-CoV, which was loaded at 250 ng/well. The N protein of SARS-CoV-2 was also loaded in each gel to determine the cross-reactivity. B, ELISA showing the reactivity of human plasma against NL63, 229E, OC43, HKU1, and SARS-CoV. Plasma samples were diluted at 1:400 to test the cross-reactivity against the N protein of SARS-CoV-2. The coating amount of N proteins was 10 ng/well. The absorbance (OD) values at 450 nm are shown on the y axis. Abbreviations: Abs, absorbance; ELISA, enzyme-linked immunosorbent assay; OD, optical density; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2.