Development of Patient-Derived Human Monoclonal Antibodies Against Nucleocapsid Protein of Severe Acute Respiratory Syndrome Coronavirus 2 for Coronavirus Disease 2019 Diagnosis

Li Zhang,Yong Qiao,Binyang Zheng,Hongxin Pan,Fengcai Zhu,Guangli Suo,Libo Zhang,Xingsu Gao

doi:10.3389/fimmu.2020.595970

Abstract

The pandemic caused by emerging Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) presents a global public health threat. Illustrating human antibody responding to viral antigen could potentially provide valuable information for basic research and clinical diagnosis. The antibody can be used as a complement to the viral detection for the rapid diagnosis of infected patients. Compared with spike protein (SP), nucleocapsid protein (NP) is normally conserved and highly immunogenic in many coronavirus members. As a major antigen, NP is a potential target for the diagnosis of SARS-CoV-2 infection. Here, we constructed a combinatorial fragment of antigen-binding (Fab)antibody phage library based on peripheral blood-derived from five coronavirus disease 2019 (COVID-19) infected donors. From the library, 159 Fab antibodies were obtained and identified by panning with NP. Among them, 16 antibodies were evaluated for their binding properties and epitopes recognition. Among these 16 antibodies, two well-paired antibodies were finally screened out for SARS-CoV-2 diagnosis by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) method. Our works may provide a potential resource for the clinical diagnosis of SARS-CoV-2 infection.

Highlights

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has spread across the globe rapidly and results in an unprecedented public health crisis [1,2,3]
After three rounds of panning, 192 randomly picked colonies were further screened by enzyme-linked immunosorbent assay (ELISA) to evaluate binding activity to SARS-CoV-2 nucleocapsid protein (NP). 178 positive clones were identified (Figure 1A)
According to the ELISA result, we found that JS08 could not pair with JS06 and JS11, and the left 13 candidate antibodies could cooperate with JS08 to capture SARS-CoV-2 NP

Summary

Introduction

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has spread across the globe rapidly and results in an unprecedented public health crisis [1,2,3]. Viral nucleic acids and viral-specific proteins can be used to detect viral infection in patients to diagnose viral infection. The quality of RT-PCR depends greatly on the quality of the throat swab and the proficiency of the experimenter. It will take several hours and require specialized reagents and instruments to perform RT-PCR. The detection of viral-specific protein has the same effect as that of nucleic acids. The proteins are more stable than RNA, and point-of-care detection reagent could be utilized in protein detection

Methods

Results

Conclusion