Major role of IgM in the neutralizing activity of convalescent plasma against SARS-CoV-2

• DOI: 10.1016/j.celrep.2021.108790
• Publication Date: 2021-02-10T17:55:56Z
• Authors: Romain Gasser; Marc Cloutier; Jérémie Prévost; Corby Fink; Éric Ducas; Shilei Ding; Nathalie Dussault; Patricia Landry; Tony Tremblay; Audrey Laforce-La...; Antoine Lewin; Guillaume Beaudoi...; Annemarie Laumaea; Halima Medjahed; Catherine Larochelle; Jonathan Richard; Gregory A. Dekaban; Jimmy D. Dikeakos; Renée Bazin; Andrés Finzi
• Keywords: Adult; Male; 0301 basic medicine; Canada; Antibodies, Viral; General Biochemistry, Genetics and Molecular Biology; Cohort Studies; Young Adult; 03 medical and health sciences; Report; Humans; COVID-19 Serotherapy; Aged; 0303 health sciences; SARS-CoV-2; Immunization, Passive; COVID-19; Middle Aged; Antibodies, Neutralizing; Immunity, Humoral; Immunoglobulin A; 3. Good health; Immunoglobulin M; Immunoglobulin G; Spike Glycoprotein, Coronavirus; Female

AbstractCharacterization of the humoral response to SARS-CoV-2, the etiological agent of Covid-19, is essential to help control the infection. In this regard, we and others recently reported that the neutralization activity of plasma from COVID-19 patients decreases rapidly during the first weeks after recovery. However, the specific role of each immunoglobulin isotype in the overall neutralizing capacity is still not well understood. In this study, we selected plasma from a cohort of Covid-19 convalescent patients and selectively depleted immunoglobulin A, M or G before testing the remaining neutralizing capacity of the depleted plasma. We found that depletion of immunoglobulin M was associated with the most substantial loss of virus neutralization, followed by immunoglobulin G. This observation may help design efficient antibody-based COVID-19 therapies and may also explain the increased susceptibility to SARS-CoV-2 of autoimmune patients receiving therapies that impair the production of IgM.