Figure 5. Reactivity of patients’ sera with native and reduced SARS-CoV-2 NP protein. Native and reduced SARS-CoV-2 NP proteins were used for coating ELISA plates, and the sera from 48 COVID-19 patients were tested against each form of protein. The total reactivity of patients’ sera with reduced NP was comparable with the corresponding reduced protein. NP: Nucleocapsid protein.