Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Protein Eng Des Sel. 2022 Feb 17;35. doi: 10.1093/protein/gzab033.
Quantification of the anti-SARS-CoV-2 antibody response has proven to be a prominent diagnostic tool during the COVID-19 pandemic. Antibody measurements have aided in the determination of humoral protection following infection or vaccination and will likely be essential for predicting the prevalence of population level immunity over the next several years. Despite widespread use, current tests remain limited in part, because antibody capture is accomplished through the use of complete spike and nucleocapsid proteins that contain significant regions of overlap with common circulating coronaviruses. To address this limitation, a unique epitope display platform utilizing monovalent display and protease-driven capture of peptide epitopes was used to select high affinity peptides. A single round of selection using this strategy with COVID-19 positive patient plasma samples revealed surprising differences and specific patterns in the antigenicity of SARS-CoV-2 proteins, especially the spike protein. Putative epitopes were assayed for specificity with convalescent and control samples, and the individual binding kinetics of peptides were also determined. A subset of prioritized peptides was used to develop an antibody diagnostic assay that showed low cross reactivity while detecting 37% more positive antibody cases than a gold standard FDA EUA test. Finally, a subset of peptides were compared with serum neutralization activity to establish a 2 peptide assay that strongly correlates with neutralization. Together, these data demonstrate a novel phage display method that is capable of comprehensively and rapidly mapping patient viral antibody responses and selecting high affinity public epitopes for the diagnosis of humoral immunity.
在 COVID-19 大流行期间，定量检测抗 SARS-CoV-2 抗体反应已被证明是一种重要的诊断工具。抗体测量有助于确定感染或接种疫苗后的体液保护作用，并且可能对于预测未来几年人群水平免疫的流行情况至关重要。尽管广泛使用，但当前的检测方法仍然存在一定的局限性，因为抗体捕获是通过使用包含与常见循环冠状病毒大量重叠区域的完整刺突和核衣壳蛋白来完成的。为了解决这一限制，利用单价展示和蛋白酶驱动的肽表位捕获的独特表位展示平台被用于选择高亲和力肽。使用这种策略对 COVID-19 阳性患者的血浆样本进行一轮选择，揭示了 SARS-CoV-2 蛋白，特别是刺突蛋白的抗原性存在惊人的差异和特定模式。针对恢复期和对照样本对假定的表位进行了特异性检测，并确定了肽的个体结合动力学。选择了一组优先肽来开发抗体诊断检测方法，该方法显示出低交叉反应性，同时比黄金标准 FDA EUA 检测方法检测到的阳性抗体病例多 37%。最后，将一组肽与血清中和活性进行比较，建立了一个与中和活性强相关的 2 肽检测方法。这些数据共同证明了一种新型的噬菌体展示方法，该方法能够全面、快速地绘制患者病毒抗体反应图谱，并选择用于诊断体液免疫的高亲和力公共表位。
