Endemic Medicine Department, Kasr Al-Aini Faculty of Medicine, Faculty of Medicine, Cairo University, Cairo, Egypt.
Endemic Medicine Department, Kasr Al-Aini Faculty of Medicine, Faculty of Medicine, Cairo University, Cairo, Egypt.
Virus Res. 2022 Oct 2;319:198852. doi: 10.1016/j.virusres.2022.198852. Epub 2022 Jul 11.
Neutralizing antibodies (NAbs) against SARS-CoV-2 infection have a pivotal role in protective immune response; however, their measurement requires specialized facilities. We evaluated the degree of correlation between NAbs and anti-SARS-CoV-2 IgG/total Ig antibodies detected by chemiluminescent immunoassay in asymptomatic and previously symptomatic SARS-CoV-2 patients.
A total of 1241 participants (previously symptomatic patients and asymptomatic individuals), who were screened for SARS-CoV-2 infection by RT-PCR or serology, were enrolled in our study. Sera were analyzed for the presence of anti-spike-1(S1)-SARS-CoV-2 IgG/total Ig antibodies, using Ortho Clinical Diagnostics, USA. A signal/cut-off value (S/CO) ≥ 1 was considered reactive. NAbs were measured in 103 random samples from groups using microneutralization assay, with titer ≥ 1:10 being considered positive.
Asymptomatic (n = 229) and 261 previously symptomatic individuals with positive serology and negative RT-PCR were finally included. Significant higher anti-S1-IgG titers were seen in asymptomatic individuals (P < 0.0001). Conversely, anti-S1-total Ig titers were significantly higher in previously symptomatic (P < 0.0001). NAbs were detected in both groups, however, higher titers were seen in previously symptomatic patients. There is a correlation between NAbs and both IgG/total anti-S1-SARS-CoV-2 antibodies (r = 0.47, P < 0.0001 and r = 0.49, P < 0.0001, respectively). IgG and total Ig could predict a neutralization titer of ≥ 1:160 at S/CO >4.44 and >65 with AUC 0.69 and 0.67, respectively.
Asymptomatic SARS-CoV-2 infection can produce comparable antibodies response to previously symptomatic individuals, however higher neutralization activity was seen in the previously symptomatic. Anti-S1-SARS-CoV-2 IgG/total Ig antibodies showed a correlation with neutralization activity and can be used to estimate the presence of protective immunity.
针对 SARS-CoV-2 感染的中和抗体（NAbs）在保护性免疫反应中起着关键作用；然而，其测量需要专门的设备。我们评估了无症状和以前有症状的 SARS-CoV-2 患者中 NAbs 与化学发光免疫分析检测到的抗 SARS-CoV-2 IgG/总 Ig 抗体之间的相关性。
共有 1241 名参与者（以前有症状的患者和无症状个体）通过 RT-PCR 或血清学筛查被纳入我们的研究。使用美国 Ortho 临床诊断公司分析血清中存在的抗刺突蛋白 1（S1）-SARS-CoV-2 IgG/总 Ig 抗体。信号/临界值（S/CO）≥1 被认为是反应性的。使用微量中和测定法在来自各组的 103 个随机样本中测量 NAbs，滴度≥1:10 被认为是阳性。
最终纳入了 229 名无症状（n=229）和 261 名以前有症状的血清学阳性和 RT-PCR 阴性个体。无症状个体的抗 S1-IgG 滴度明显较高（P<0.0001）。相反，以前有症状的个体的抗 S1-总 Ig 滴度明显较高（P<0.0001）。在两组中均检测到 NAbs，但以前有症状的患者中滴度更高。NAbs 与 IgG/总抗 S1-SARS-CoV-2 抗体之间存在相关性（r=0.47，P<0.0001 和 r=0.49，P<0.0001）。IgG 和总 Ig 可以预测 S/CO >4.44 和 >65 时中和滴度≥1:160，AUC 分别为 0.69 和 0.67。
无症状 SARS-CoV-2 感染可产生与以前有症状个体相当的抗体反应，但以前有症状的个体中观察到更高的中和活性。抗 S1-SARS-CoV-2 IgG/总 Ig 抗体与中和活性相关，可用于估计保护性免疫的存在。
