Antibody responses in COVID-19 patients could guide vaccine design

A comprehensive analysis of antibody responses in coronavirus disease 2019 (COVID-19) patients could inform the development of an effective vaccine, according to a study published September 10 in the open-access journal PLOS Pathogens by Chao Wu and Rui Huang of Nanjing University Medical School, and colleagues. The results show that the neutralizing activity of antibodies from recovered patients is typically not strong, and declines sharply within one month after hospital discharge.

The world is facing an unprecedented challenge with communities and economies affected by the growing COVID-19 pandemic. Currently, there is no vaccine or effective drugs approved to treat or prevent the disease. A better understanding of antibody responses against SARS-CoV-2 — the virus that causes COVID-19 — will provide fundamental information for developing effective treatments and a preventive vaccine. In the new study, researchers continuously monitored SARS-CoV-2-specific antibody responses in 19 non-severe and seven severe COVID-19 patients for seven weeks from disease onset.

Most patients generated antibody responses against SARS-CoV-2, including the viral nucleoprotein and three parts of the spike protein: the receptor-binding domain, S1 protein, and ectodomain. Although 80.7% of recovered COVID-19 patients had varying levels of antibody neutralization activity against SARS-CoV-2, only a small portion of patients elicited a potent level of neutralization activity. This result highlights the importance of carefully selecting blood samples from recovered patients using antibody neutralization assays prior to transfusion into other COVID-19 patients. Three to four weeks after hospital discharge, the neutralizing activity of antibodies from recovered patients declined significantly, suggesting that recovered COVID-19 patients might be susceptible to reinfection with SARS-CoV-2. In addition, severe COVID-19 patients had a large amount of non-neutralizing antibodies, which may contribute to antibody-dependent enhancement of infection. According to the authors, the study provides important insights for serological testing, antibody-based intervention, and vaccine design.

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Peer reviewed; Experimental study; People

Funding: This study was supported by the Fundamental Research Funds for the Central Universities (No. 14380459 to CW). the Medical Science and technology Development Foundation, Nanjing Department of Health (YKK19056 to YC), Nanjing Medical Science and Technique Development Foundation (QRX17141 to YC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.

Citation: Chen Y, Tong X, Li Y, Gu B, Yan J, Liu Y, et al. (2020) A comprehensive, longitudinal analysis of humoral responses specific to four recombinant antigens of SARS-CoV-2 in severe and non-severe COVID-19 patients. PLoS Pathog 16(9): e1008796. https://doi.org/10.1371/journal.ppat.1008796

Department of Laboratory Medicine, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, Jiangsu, China

Medical Technology School of Xuzhou Medical University, Xuzhou Key Laboratory of Laboratory Diagnostics, Xuzhou, Jiangsu, China

Department of Laboratory Medicine, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China

In your coverage please use this URL to provide access to the freely available paper: http://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008796