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. 2022 Jan 21;149(4):1225–1241. doi: 10.1016/j.jaci.2022.01.005

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© 2022 American Academy of Allergy, Asthma & Immunology.

Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

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Fig 1 — Longitudinal dynamics of antibody responses in COVID-19 patients. A, Schematic of the study design. A total of 31 SARS-CoV-2–infected individuals and 20 healthy donors were enrolled onto the study. Serum sample collection was performed longitudinally at multiple time points for 20 patients among 31 SARS-CoV-2–infected individuals, while sampling at a single time point was conducted for the other 11 patients. The number of participants and serum samples used in various assays are listed. B and C, A total of 101 serum samples from 31 COVID-19 patients were tested by ELISA for SARS-CoV-2 N protein (B) and S protein (C) binding IgG antibodies at different time points after symptom onset (days 1-30, n = 37; days 31-61, n = 18; days 100-150, n = 21; days 180-220, n = 25). Serum samples from 20 healthy donors were included as the control group. D, NT₅₀ against SARS-CoV-2 pseudoviruses over time was calculated by nonlinear regression. E, Distribution of serum neutralizing activity in COVID-19 patients at indicated time points after disease onset are presented. Samples with a NT₅₀ titer below 20 were defined as no neutralizing activity. F, Correlation analysis between log₁₀ serum end point titers of SARS-CoV-2 S protein–specific IgG antibodies and N protein-binding IgG antibodies (n = 101). G and H, Correlations of serum neutralizing titers against SARS-CoV-2 with end point titers of N protein (G) or S protein binding (H) IgG antibodies. I, Serum samples obtained from COVID-19 patients at indicated time points after disease onset were evaluated for the cross-binding to SARS-CoV and MERS-CoV S proteins as well as the cross-neutralizing activity against SARS-CoV and MERS-CoV pseudoviruses. For cross-binding and SARS-CoV cross-neutralizing, the cutoff value for the positive response was set as the mean plus 2× SD of serum binding end point titers or NT₅₀ values of 20 healthy donors. For MERS-CoV cross-neutralizing, samples with a NT₅₀ of >20 (the lowest serum dilution) were considered positive. Small horizontal solid lines in (B-D) indicate the mean value of each group; dotted lines represent the lowest serum dilution in each test. Statistical significances were determined by 1-way ANOVA with Tukey multiple comparison. ∗P < .05, ∗∗P < .01, and ∗∗∗∗P < .0001. Correlation analyses in (F-H) were calculated by Pearson correlation test.