Recovery of Memory B-cell Subsets and Persistence of Antibodies in Convalescent COVID-19 Patients

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  • 1 ICER-ICMR-NIRT-International Center for Excellence in Research, Chennai, Tamil Nadu, India;
  • | 2 Immunology-ICMR-National Institute for Research in Tuberculosis, Chennai, Tamil Nadu, India;
  • | 3 ICMR-National Institute of Epidemiology, Chennai, Tamil Nadu, India

It is essential to examine the longevity of the defensive immune response engendered by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. We examined the SARS-CoV-2-specific antibody responses and ex vivo memory B-cell subsets in seven groups of individuals with COVID-19 classified based on days since reverse-transcription polymerase chain reaction confirmation of SARS-CoV-2 infection. Our data showed that the levels of IgG and neutralizing antibodies started increasing from days 15 to 30 to days 61 to 90, and plateaued thereafter. The frequencies of naive B cells and atypical memory B cells decreased from days 15 to 30 to days 61 to 90, and plateaued thereafter. In contrast, the frequencies of immature B cells, classical memory B cells, activated memory B cells, and plasma cells increased from days 15 to 30 to days 61 to 90, and plateaued thereafter. Patients with severe COVID-19 exhibited increased frequencies of naive cells, atypical memory B cells, and activated memory B cells, and lower frequencies of immature B cells, central memory B cells, and plasma cells when compared with patients with mild COVID-19. Therefore, our data suggest modifications in memory B-cell subset frequencies and persistence of humoral immunity in convalescent individuals with COVID-19.

Author Notes

Address correspondence to Anuradha Rajamanickam, ICER-ICMR-NIRT-International Center for Excellence in Research, Chennai, Tamil Nadu, India. E-mail: anuradha@nirt.res.in

These authors contributed equally to this work.

Financial support: This work was supported by NIRT-ICER and ICMR-NIE.

Authors’ addresses: Anuradha Rajamanickam, ICER-ICMR-NIRT-International Center for Excellence in Research, Chennai, Tamil Nadu, India, E-mail: anuradha@nirt.res.in. Nathella Pavan Kumar, Arul Nancy P, Nandhini Selvaraj, Saravanan Munisankar, Rachel Mariam Renji, and Vijayalakshmi V, ICMR-National Institute for Research in Tuberculosis, Chennai, India, E-mails: pavankumarn@nirt.res.in, arul.p@nirt.res.in, nandhu30797@gmail.com, saravanan.m@nirt.res.in, rachelmr1610@gmail.com, and divurockz99@gmail.com. Manoj Murhekar, Jeromie Wesley Vivian Thangaraj, Muthusamy Santhosh Kumar, C. P. Girish Kumar, Tarun Bhatnagar, Manickam Ponnaiah, R. Sabarinathan, and V. Saravana Kumar, National Institute of Epidemiology (ICMR), Second Main Road, Tamil Nadu Housing Board, Ayapakkam, Near Ambattur, Chennai, E-mails: mmurhekar@nieicmr.org.in, stanjeromie@nieicmr.org.in, santhoshkumar@nieicmr.org.in, girishmicro@gmail.com, drtarunb@gmail.com, manickam@nie.gov.in, sabari@nieicmr.org.in, and saravanan.biostat1985@gmail.com. Subash Babu, ICMR-NIRT-International Center for Excellence in Research, Chennai, E-mail: sbabu@nirt.res.in.

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