Neutralization of SARS-CoV-2 with IgG from COVID-19-convalescent plasma

• Published in: Scientific reports Vol. 11; no. 1; pp. 5563 - 12
• Main Authors: Maeda, Kenji, Higashi-Kuwata, Nobuyo, Kinoshita, Noriko, Kutsuna, Satoshi, Tsuchiya, Kiyoto, Hattori, Shin-ichiro, Matsuda, Kouki, Takamatsu, Yuki, Gatanaga, Hiroyuki, Oka, Shinichi, Sugiyama, Haruhito, Ohmagari, Norio, Mitsuya, Hiroaki
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.03.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/250/251; 631/250/255/2514; 631/326/596/4130; Adult; Aged; Aged, 80 and over; Antibodies, Neutralizing - immunology; Antibodies, Viral - immunology; Coronaviruses; COVID-19; COVID-19 - immunology; COVID-19 - prevention & control; COVID-19 - therapy; COVID-19 Serotherapy; Female; Humanities and Social Sciences; Humans; Immune response; Immunization, Passive - methods; Immunoglobulin G; Immunoglobulin G - immunology; Male; Middle Aged; multidisciplinary; Neutralization; Pandemics - prevention & control; Plasma - chemistry; Receptors, Virus - metabolism; SARS-CoV-2 - immunology; SARS-CoV-2 - pathogenicity; Science; Science (multidisciplinary); Severe acute respiratory syndrome coronavirus 2
• DOI: 10.1038/s41598-021-84733-5
• ISSN: 2045-2322

While there are various attempts to administer COVID-19-convalescent plasmas to SARS-CoV-2-infected patients, neither appropriate approach nor clinical utility has been established. We examined the presence and temporal changes of the neutralizing activity of IgG fractions from 43 COVID-19-convalescent plasmas using cell-based assays with multiple endpoints. IgG fractions from 27 cases (62.8%) had significant neutralizing activity and moderately to potently inhibited SARS-CoV-2 infection in cell-based assays; however, no detectable neutralizing activity was found in 16 cases (37.2%). Approximately half of the patients (~ 41%), who had significant neutralizing activity, lost the neutralization activity within ~ 1 month. Despite the rapid decline of neutralizing activity in plasmas, good amounts of SARS-CoV-2-S1-binding antibodies were persistently seen. The longer exposure of COVID-19 patients to greater amounts of SARS-CoV-2 elicits potent immune response to SARS-CoV-2, producing greater neutralization activity and SARS-CoV-2-S1-binding antibody amounts. The dilution of highly-neutralizing plasmas with poorly-neutralizing plasmas relatively readily reduced neutralizing activity. The presence of good amounts of SARS-CoV-2-S1-binding antibodies does not serve as a surrogate ensuring the presence of good neutralizing activity. In selecting good COVID-19-convalescent plasmas, quantification of neutralizing activity in each plasma sample before collection and use is required.