Anti-coronavirusdisease-2019 (COVID-19; anti-severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2)) antibodies against nucleoprotein (NP) were purified from pig sera. Following the separation of the antibody fraction using a protein-A column, the final yield of the purified antibodies against SARS-CoV-2 NPs was estimated to be 0.26 ± 0.05 % (absolute amount of 143.4 ± 25.2 ng, n=5) from 1 mL of pig sera. The binding activities of the isolated antibodies were confirmed using immunoassay and immunostaining. Based on the specific binding activity to NPs, a quantitative assay was performed using a surface plasmon resonance (SPR) biosensor. From the doseresponse curve, the binding constant (Kd) was calculated to be 185 pM and the limit of detection was estimated to be 1.02 pM. The SPR biosensor with the isolated antibodies against SARS-CoV-2 NPs was applied for the detection of SARS-CoV-2, MERS-CoV, and CoV strain 229E in culture fluid.

从猪血清中纯化了针对核蛋白（NP）的抗冠状病毒病-2019（COVID-19;抗重症急性呼吸系统综合症冠状病毒2（SARS-CoV-2））抗体。使用蛋白A柱分离抗体级分后，针对SARS-CoV-2 NP的纯化抗体最终收率估计为0.26±0.05％（绝对量为143.4±25.2 ng，n = 5）， 1 mL猪血清。分离的抗体的结合活性通过免疫测定和免疫染色得到证实。基于对NP的特异性结合活性，使用表面等离振子共振（SPR）生物传感器进行了定量分析。从剂量反应曲线计算出结合常数（Kd）为185 pM，检测极限估计为1.02 pM。