Management of the COVID-19 pandemic relies on molecular diagnostic methods supported by serological tools. Herein, we developed S-RBD- and N- based ELISA assays useful for infection rate surveillance as well as the follow-up of acquired protective immunity against SARS-CoV-2. ELISA assays were optimized using COVID-19 Tunisian patients’ sera and prepandemic controls. Assays were further validated in 3 African countries with variable endemic settings. The receiver operating curve was used to evaluate the assay performances. The N- and S-RBD-based ELISA assays performances, in Tunisia, were very high (AUC: 0.966 and 0.98, respectively, p < 0.0001). Cross-validation analysis showed similar performances in different settings. Cross-reactivity, with malaria infection, against viral antigens, was noticed. In head-to-head comparisons with different commercial assays, the developed assays showed high agreement. This study demonstrates, the added value of the developed serological assays in low-income countries, particularly in ethnically diverse populations with variable exposure to local endemic infectious diseases.
【저자키워드】 COVID-19, COVID-19, Coronavirus disease 2019, ELISA, S-RBD, SARS-CoV, severe acute respiratory syndrome coronavirus, ELISA, enzyme-linked immunosorbent assay, MERS-CoV, Middle East respiratory syndrome coronavirus, HRP, horseradish peroxidase, PBS, phosphate buffered saline, ROC, Receiver operating curve, RT-PCR, Reverse transcription polymerase chain reaction, S, spike protein, N, nucleocapsid protein, M, Membrane protein, E, Envelope protein, AUC, area under curve, E. coli, Escherichia coli, Endemic African settings, IPTG, isopropyl-β-D-thiogalactopyranoside, LB, luria broth, LIPS, luciferase immunoprecipitation system, MALDI-TOF, matrix assisted laser desorption ionization-time of flight, Multicentric validation, Nucleoprotein N, S-RBD, receptor-binding domain of the spike protein, TMB, 3,3′,5,5′-tetramethylbenzidine,