Neutralizing Antibody Responses in COVID-19 Convalescent Sera

0 views • Oct 30, 2021


Author Name

William T Lee

Karen E Kulas

Anne F. Payne

Susan J Wong

Jeffrey Jhang

Ania Wajnberg


Florian Krammer

Brad Hutton

Jill Taylor

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Passive transfer of antibodies from COVID-19 convalescent patients is being used as an experimental treatment for eligible patients with SARS-CoV-2 infections. The United States Food and Drug Administration's (FDA) guidelines for convalescent plasma recommends target antibody titers of 160. We evaluated SARS-CoV-2 neutralizing antibodies in sera from recovered COVID-19 patients using plaque reduction neutralization tests (PRNT) at low (PRNT50) and high (PRNT90) stringency thresholds. We found that neutralizing activity increased with time post symptom onset (PSO), reaching a peak at 31-35 days PSO. At this point, the number of sera having neutralizing titers of at least 160 was ~93% (PRNT50) and ~54% (PRNT90). Sera with high SARS-CoV-2 antibody levels ([≥]960 ELISA titers) showed maximal activity, but not all high titer sera contained neutralizing antibody at FDA recommended levels, particularly at high stringency. These results underscore the value of serum characterization for neutralization activity.

Key Words
Key Words 41 Projects
SARS-CoV-2 42 Projects
Infectious Diseases
Infectious Diseases 62 Projects
COVID-19 47 Projects
Convalescent Plasma
Convalescent Plasma 2 Projects