Whitcombe Alana L, McGregor Reuben, Craigie Alyson, James Alex, Charlewood Richard, Lorenz Natalie, Dickson James Mj, Sheen Campbell R, Koch Barbara, Fox-Lewis Shivani, McAuliffe Gary, Roberts Sally A, Morpeth Susan C, Taylor Susan, Webb Rachel H, Jack Susan, Upton Arlo, Ussher James E, Moreland Nicole J
Faculty of Medical and Health Sciences University of Auckland Auckland New Zealand.
Maurice Wilkins Centre University of Auckland Auckland New Zealand.
Clin Transl Immunology. 2021 Mar 14;10(3):e1261. doi: 10.1002/cti2.1261. eCollection 2021.
Circulating antibodies are important markers of previous infection and immunity. Questions remain with respect to the durability and functionality of SARS-CoV-2 antibodies. This study explored antibody responses in recovered COVID-19 patients in a setting where the probability of re-exposure is effectively nil, owing to New Zealand's successful elimination strategy.
A triplex bead-based assay that detects antibody isotype (IgG, IgM and IgA) and subclass (IgG1, IgG2, IgG3 and IgG4) responses against Nucleocapsid (N) protein, the receptor binding domain (RBD) and Spike (S) protein of SARS-CoV-2 was developed. After establishing baseline levels with pre-pandemic control sera ( = 113), samples from PCR-confirmed COVID-19 patients with mild-moderate disease ( = 189) collected up to 8 months post-infection were examined. The relationship between antigen-specific antibodies and neutralising antibodies (NAbs) was explored with a surrogate neutralisation assay that quantifies inhibition of the RBD/hACE-2 interaction.
While most individuals had broad isotype and subclass responses to each antigen shortly after infection, only RBD and S protein IgG, as well as NAbs, were relatively stable over the study period, with 99%, 96% and 90% of samples, respectively, having responses over baseline 4-8 months post-infection. Anti-RBD antibodies were strongly correlated with NAbs at all time points (Pearson's ≥ 0.87), and feasibility of using finger prick sampling to accurately measure anti-RBD IgG was demonstrated.
Antibodies to SARS-CoV-2 persist for up to 8 months following mild-to-moderate infection. This robust response can be attributed to the initial exposure without immune boosting given the lack of community transmission in our setting.
循环抗体是既往感染和免疫的重要标志物。关于严重急性呼吸综合征冠状病毒2（SARS-CoV-2）抗体的持久性和功能仍存在疑问。本研究在新西兰成功的消除策略使再次暴露的可能性几乎为零的背景下，探索了康复的2019冠状病毒病（COVID-19）患者的抗体反应。
开发了一种基于三重微珠的检测方法，用于检测针对SARS-CoV-2核衣壳（N）蛋白、受体结合域（RBD）和刺突（S）蛋白的抗体同种型（IgG、IgM和IgA）和亚类（IgG1、IgG2、IgG3和IgG4）反应。在用大流行前对照血清（n = 113）建立基线水平后，对PCR确诊的轻度至中度疾病COVID-19患者（n = 189）在感染后长达8个月收集的样本进行检测。通过一种替代中和试验探索了抗原特异性抗体与中和抗体（NAbs）之间的关系，该试验可量化对RBD/hACE-2相互作用的抑制。
虽然大多数个体在感染后不久对每种抗原都有广泛的同种型和亚类反应，但在研究期间只有RBD和S蛋白IgG以及NAbs相对稳定，感染后4 - 8个月分别有99%、96%和90%的样本反应高于基线。抗RBD抗体在所有时间点与NAbs都有很强的相关性（Pearson's r≥0.87），并证明了使用手指针刺采样准确测量抗RBD IgG的可行性。
轻度至中度感染后，SARS-CoV-2抗体可持续长达8个月。鉴于我们所处环境中缺乏社区传播，这种强烈反应可归因于初次暴露而没有免疫增强。
