Switched and unswitched memory B cells detected during SARS-CoV-2 convalescence correlate with limited symptom duration

• Published in: PloS one Vol. 16; no. 1; p. e0244855
• Main Authors: Newell, Krista L., Clemmer, Deanna C., Cox, Justin B., Kayode, Yetunde I., Zoccoli-Rodriguez, Victoria, Taylor, Harry E., Endy, Timothy P., Wilmore, Joel R., Winslow, Gary M.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 28.01.2021; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Antibodies; Antibodies, Neutralizing - immunology; Antibodies, Viral - immunology; Antibody Formation; B cells; B-Lymphocyte Subsets - immunology; B-Lymphocytes - immunology; Biology and Life Sciences; CD16 antigen; Cell suspensions; Convalescence; Coronaviruses; COVID-19; COVID-19 - immunology; Cytokines; Disease Progression; Editing; Epidemics; Female; Flow cytometry; Funding; Global health; Health aspects; Humans; Immune response; Immune system; Immunity - immunology; Immunoglobulin G - immunology; Immunoglobulin M - metabolism; Immunological memory; Immunology; Immunophenotyping - methods; Infections; Lymphocytes; Lymphocytes B; Lymphocytes T; Male; Medical research; Medicine and Health Sciences; Memory cells; Microbiology; Middle Aged; Observations; Physiological aspects; Physiological research; Plasma; Public health; Recovery of Function - immunology; Research and Analysis Methods; SARS-CoV-2 - immunology; SARS-CoV-2 - isolation & purification; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Sodium azide; Sodium azides; Software; United States; Viral diseases; United States; New York; United States > US
• DOI: 10.1371/journal.pone.0244855
• ISSN: 1932-6203

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of the pandemic human respiratory illness COVID-19, is a global health emergency. While severe acute disease has been linked to an expansion of antibody-secreting plasmablasts, we sought to identify B cell responses that correlated with positive clinical outcomes in convalescent patients. We characterized the peripheral blood B cell immunophenotype and plasma antibody responses in 40 recovered non-hospitalized COVID-19 subjects that were enrolled as donors in a convalescent plasma treatment study. We observed a significant negative correlation between the frequency of peripheral blood memory B cells and the duration of symptoms for convalescent subjects. Memory B cell subsets in convalescent subjects were composed of classical CD24 + class-switched memory B cells, but also activated CD24-negative and natural unswitched CD27 + IgD + IgM + subsets. Memory B cell frequency was significantly correlated with both IgG1 and IgM responses to the SARS-CoV-2 spike protein receptor binding domain (RBD) in most seropositive subjects. IgM + memory, but not switched memory, directly correlated with virus-specific antibody responses, and remained stable over 3 months. Our findings suggest that the frequency of memory B cells is a critical indicator of disease resolution, and that IgM + memory B cells may play an important role in SARS-CoV-2 immunity.