Dynamic anti-spike protein antibody profiles in COVID-19 patients

• Published in: International journal of infectious diseases 2021-02, Vol.103, p.540-548
• Main Authors: Bao, Yujie, Ling, Yun, Chen, Ying-ying, Tian, Di, Zhao, Guo-ping, Zhang, Xiang-hui, Hang, Hong, Li, Yu, Su, Bing, Lu, Hong-zhou, Xu, Jie, Wang, Ying
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Antibodies, Viral - blood; COVID-19; COVID-19 - diagnosis; COVID-19 Testing; Dynamics; Female; Humans; IgG and IgM; Immunoglobulin G - blood; Immunoglobulin M - blood; Male; Middle Aged; SARS-CoV-2; SARS-CoV-2 - immunology; Spike glycoprotein; Spike Glycoprotein, Coronavirus - immunology
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2020.12.014

•Total T lymphocyte count and CD4+ T cells decrease in the early stage of COVID-19.•The window periods of anti-Spike IgG and IgM is day 14 and 10, respectively.•96% recovered plasma exhibited IgG and IgM targeting only the CTD of S1 fragment. This study intended to investigate the dynamics of anti-spike (S) IgG and IgM antibodies in COVID-19 patients. Anti-S IgG/IgM was determined by a semi-quantitative fluorescence immunoassay in the plasma of COVID-19 patients at the manifestation and rehabilitation stages. The immunoreactivity to full-length S proteins, C-terminal domain (CTD), and N-terminal domain (NTD) of S1 fragments were determined by an ELISA assay. Clinical properties at admission and discharge were collected simultaneously. The positive rates of anti-S IgG/IgM in COVID-19 patients were elevated after rehabilitation compared to the in-patients. Anti-S IgG and IgM were not apparent until day 14 and day ten, respectively, according to Simple Moving Average analysis with five days’ slide window deduction. More than 90% of the rehabilitation patients exhibited IgG and IgM responses targeting CTD-S1 fragments. Decreased total peripheral lymphocytes, CD4+ and CD8+ T cell counts were seen in COVID-19 patients at admission and recovered after the rehabilitation. Anti-S IgG and IgM do not appear at the onset with the decrease in T cells, making early serological screening less significant. However, the presence of high IgG and IgM to S1-CTD in the recovered patients highlights humoral responses after SARS-CoV-2 infection, which might be associated with efficient immune protection in COVID-19 patients.