Longevity of memory B cells and antibodies, as well as the polarization of effector memory helper T cells, are associated with disease severity in patients with COVID-19 in Bangladesh Marjahan Akhtar 1 , Salima Raiyan Basher 1 , Nuder Nower Nizam 1 , Mohammad Kamruzzaman 1 , Fatema Khaton 1 , Hasan Al Banna 1 , M Hasanul Kaisar 1 , Polash Chandra Karmakar 1 , Al Hakim 1,2 , Afroza Akter 1 , Tasnuva Ahmed 1 , Imam Tauheed 1 , Shaumik Islam 1 , Faisal Ahmmed 1 , Shakil Mahamud 1 , Mohammad Abul Hasnat 3 , Mostafa Aziz Sumon 3 , Asif Rashed 4 , Shuvro Ghosh 4 , Stephen B. Calderwood 5 , Jason B. Harris 5,6 , Richelle C. Charles 5,6,7 , Regina C. LaRocque 5,6 , Edward T. Ryan 5,6,7 , Sayera Banu 1 , Tahmina Shirin 8 , Fahima Chowdhury 1† , Taufiqur Rahman Bhuiyan 1† and Firdausi Qadri 1 * † 1 Infectious Diseases Division, International Centre for Diarrhoeal Disease Research Bangladesh (ICDDRB), Dhaka, Bangladesh, 2 Department of Genetic Engineering and Biotechnology, Jagannath University, Dhaka, Bangladesh, 3 Department of Cardiology, Department of Oncology, Kurmitola General Hospital, Dhaka, Bangladesh, 4 Department of Microbiology, Department of Medicine, Mugda Medical College and Hospital, Dhaka, Bangladesh, 5 Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, United States, 6 Departments of Medicine and Pediatrics, Harvard Medical School, Boston, MA, United States, 7 Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, United States, 8 Institute of Epidemiology, Disease Control and Research (IEDCR), Dhaka, Bangladesh The longevity of immune responses induced by different degrees of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection provides information important to understanding protection against coronavirus disease 2019 (COVID-19). Here, we report the persistence of SARS-CoV-2 spike receptor-binding domain (RBD) specific antibodies and memory B cells recognizing this antigen in sequential samples from patients in Bangladesh with asymptomatic, mild, moderate and severe COVID-19 out to six months following infection. Since the development of long-lived memory B cells, as well as antibody production, is likely to be dependent on T helper (Th) cells, we also investigated the phenotypic changes of Th cells in COVID-19 patients over time following infection. Our results show that patients with moderate to severe COVID-19 mounted significant levels of IgG antibodies out to six Frontiers in Immunology frontiersin.org 01 OPEN ACCESS EDITED BY Tara Marlene Strutt, University of Central Florida, United States REVIEWED BY Emily S.J. Edwards, Monash University, Australia Daniel Lingwood, Ragon Institute, United States *CORRESPONDENCE Firdausi Qadri fqadri@icddrb.org † These authors share senior authorship SPECIALTY SECTION This article was submitted to Immunological Memory, a section of the journal Frontiers in Immunology RECEIVED 23 September 2022 ACCEPTED 23 November 2022 PUBLISHED 12 December 2022 CITATION Akhtar M, Basher SR, Nizam NN, Kamruzzaman M, Khaton F, Banna HA, Kaisar MH, Karmakar PC, Hakim A, Akter A, Ahmed T, Tauheed I, Islam S, Ahmmed F, Mahamud S, Hasnat MA, Sumon MA, Rashed A, Ghosh S, Calderwood SB, Harris JB, Charles RC, LaRocque RC, Ryan ET, Banu S, Shirin T, Chowdhury F, Bhuiyan TR and Qadri F (2022) Longevity of memory B cells and antibodies, as well as the polarization of effector memory helper T cells, are associated with disease severity in patients with COVID-19 in Bangladesh. Front. Immunol. 13:1052374. doi: 10.3389/fimmu.2022.1052374 TYPE Original Research PUBLISHED 12 December 2022 DOI 10.3389/fimmu.2022.1052374