Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205 Moscow, Russia.
Institute of Cell Biophysics, Russian Academy of Sciences, Federal Research Centre "Pushchino Scientific Centre of Biological Research of Russian Academy of Sciences", Institutskaya 3, 142290 Pushchino, Russia.
Viruses. 2021 Sep 28;13(10):1945. doi: 10.3390/v13101945.
Since SARS-CoV-2 appeared in late 2019, many studies on the immune response to COVID-19 have been conducted, but the asymptomatic or light symptom cases were somewhat understudied as respective individuals often did not seek medical help. Here, we analyze the production of the IgG antibodies to viral nucleocapsid (N) protein and receptor-binding domain (RBD) of the spike protein and assess the serum neutralization capabilities in a cohort of patients with different levels of disease severity. In half of light or asymptomatic cases the antibodies to the nucleocapsid protein, which serve as the main target in many modern test systems, were not detected. They were detected in all cases of moderate or severe symptoms, and severe lung lesions correlated with respective higher signals. Antibodies to RBD were present in the absolute majority of samples, with levels being sometimes higher in light symptom cases. We thus suggest that the anti-RBD/anti-N antibody ratio may serve as an indicator of the disease severity. Anti-RBD IgG remained detectable after a year or more since the infection, even with a slight tendency to raise over time, and the respective signal correlated with the serum capacity to inhibit the RBD interaction with the ACE-2 receptor.
自 2019 年底 SARS-CoV-2 出现以来，已经进行了许多关于 COVID-19 免疫反应的研究，但由于无症状或轻症病例的个体通常不会寻求医疗帮助，因此对这些病例的研究相对较少。在这里，我们分析了一组不同严重程度疾病患者的病毒核衣壳（N）蛋白和刺突蛋白受体结合域（RBD）的 IgG 抗体产生情况，并评估了血清中和能力。在半数轻度或无症状病例中，未能检测到作为许多现代检测系统主要靶标的核衣壳蛋白抗体。在所有中度或重度症状的病例中都检测到了这些抗体，并且严重的肺部病变与相应的更高信号相关。RBD 抗体存在于绝大多数样本中，在轻症病例中的水平有时更高。因此，我们认为抗 RBD/抗 N 抗体比值可作为疾病严重程度的指标。感染一年多后，抗 RBD IgG 仍可检测到，即使随着时间的推移略有升高趋势，相应的信号与抑制 RBD 与 ACE-2 受体相互作用的血清能力相关。
