Department of Microbiology and Medical Zoology, University of Puerto Rico-Medical Sciences Campus, San Juan, PR 00936, USA.
Unit of Comparative Medicine, University of Puerto Rico-Medical Sciences Campus, San Juan, PR 00936, USA.
Viruses. 2021 Sep 30;13(10):1972. doi: 10.3390/v13101972.
Both the SARS-CoV-2 pandemic and emergence of variants of concern have highlighted the need for functional antibody assays to monitor the humoral response over time. Antibodies directed against the spike (S) protein of SARS-CoV-2 are an important component of the neutralizing antibody response. In this work, we report that in a subset of patients-despite a decline in total S-specific antibodies-neutralizing antibody titers remain at a similar level for an average of 98 days in longitudinal sampling of a cohort of 59 Hispanic/Latino patients exposed to SARS-CoV-2. Our data suggest that 100% of seroconverting patients make detectable neutralizing antibody responses which can be quantified by a surrogate viral neutralization test. Examination of sera from ten out of the 59 subjects which received mRNA-based vaccination revealed that both IgG titers and neutralizing activity of sera were higher after vaccination compared to a cohort of 21 SARS-CoV-2 naïve subjects. One dose was sufficient for the induction of a neutralizing antibody, but two doses were necessary to reach 100% surrogate virus neutralization in subjects irrespective of previous SARS-CoV-2 natural infection status. Like the pattern observed after natural infection, the total anti-S antibodies titers declined after the second vaccine dose; however, neutralizing activity remained relatively constant for more than 80 days after the first vaccine dose. Furthermore, our data indicates that-compared with mRNA vaccination-natural infection induces a more robust humoral immune response in unexposed subjects. This work is an important contribution to understanding the natural immune response to the novel coronavirus in a population severely impacted by SARS-CoV-2. Furthermore, by comparing the dynamics of the immune response after the natural infection vs. the vaccination, these findings suggest that functional neutralizing antibody tests are more relevant indicators than the presence or absence of binding antibodies.
SARS-CoV-2 大流行和关注变种的出现突出表明，需要功能抗体检测来随时间监测体液反应。针对 SARS-CoV-2 刺突（S）蛋白的抗体是中和抗体反应的重要组成部分。在这项工作中，我们报告在一组 59 名接触 SARS-CoV-2 的西班牙裔/拉丁裔患者的纵向样本中，尽管总 S 特异性抗体下降，但在平均 98 天的时间内，中和抗体滴度仍保持在相似水平。我们的数据表明，100%的血清转化患者产生可检测的中和抗体反应，可通过替代病毒中和试验进行定量。检查 59 名受试者中的 10 名接受基于 mRNA 的疫苗接种的血清，发现与 21 名 SARS-CoV-2 未感染的受试者相比，接种后血清 IgG 滴度和中和活性均更高。一剂足以诱导中和抗体，但两剂均足以在无论先前 SARS-CoV-2 自然感染状况如何的受试者中达到 100%替代病毒中和。与自然感染后观察到的模式一样，总抗 S 抗体滴度在第二剂疫苗后下降；然而，中和活性在第一剂疫苗后 80 多天内保持相对稳定。此外，我们的数据表明，与 mRNA 疫苗接种相比，自然感染在未暴露的受试者中诱导更强大的体液免疫反应。这项工作是对严重受 SARS-CoV-2 影响的人群中新型冠状病毒自然免疫反应的重要贡献。此外，通过比较自然感染和疫苗接种后的免疫反应动态，这些发现表明功能中和抗体检测是比存在或不存在结合抗体更相关的指标。
