Antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleoprotein (NP) were purified from pig serum through two steps: (1) isolation of anti-NP IgG antibodies using magnetic beads with immobilized human SARS-CoV-2 NP and (2) filtration of anti-spike protein (SP) IgG antibodies using magnetic beads with immobilized human SARS-CoV SP. The enhanced specificity of the purified antibodies to the NP of SARS-CoV-2 was demonstrated using an immunoassay with anti-NP IgG antibodies after the isolation and filtration steps. The binding constants (K_d) of the purified anti-NP IgG antibodies to the NP of SARS-CoV-2 and the SP of SARS-CoV were estimated using a surface plasmon resonance biosensor (SPR). A competitive assay using the two-step purified anti-NP IgG antibodies from pig serum demonstrated (a) the detection of SARS-CoV-2 in viral fluid and (b) the discrimination of SARS-CoV-2 from SARS-CoV, MERS-CoV, and CoV strain 229E in viral fluids.

通过两个步骤从猪血清中纯化出针对严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）核蛋白（NP）的抗体：（1）使用固定了人源SARS-CoV-2 NP的磁珠分离抗NP IgG抗体（2）使用磁珠和固定的人SARS-CoV SP过滤抗钉蛋白（SP）IgG抗体。在分离和过滤步骤后，使用具有抗NP IgG抗体的免疫测定法证明了纯化的抗体对SARS-CoV-2 NP的特异性增强。结合常数（K _d使用表面等离振子共振生物传感器（SPR）估算纯化的抗SARS-CoV-2 NP的抗NP IgG抗体和SARS-CoV的SP。使用来自猪血清的两步纯化抗NP IgG抗体进行的竞争性测定证明（a）检测到病毒液中的SARS-CoV-2，并且（b）区分SARS-CoV-2与SARS-CoV，MERS -CoV和病毒液中的CoV毒株229E。