Enhanced SARS-CoV-2-Specific CD4<sup>+</sup> T Cell Activation and Multifunctionality in Late Convalescent COVID-19 Individuals
Nathella Pavan Kumar,
Kadar Moideen,
Arul Nancy,
Nandhini Selvaraj,
Rachel Mariam Renji,
Saravanan Munisankar,
Jeromie Wesley Vivian Thangaraj,
Santhosh Kumar Muthusamy,
C. P. Girish Kumar,
Tarun Bhatnagar,
Manickam Ponnaiah,
Sabarinathan Ramasamy,
Saravanakumar Velusamy,
Manoj Vasant Murhekar,
Subash Babu
Affiliations
Nathella Pavan Kumar
Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Kadar Moideen
International Center for Excellence in Research, Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Arul Nancy
International Center for Excellence in Research, Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Nandhini Selvaraj
International Center for Excellence in Research, Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Rachel Mariam Renji
International Center for Excellence in Research, Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Saravanan Munisankar
International Center for Excellence in Research, Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Jeromie Wesley Vivian Thangaraj
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Santhosh Kumar Muthusamy
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
C. P. Girish Kumar
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Tarun Bhatnagar
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Manickam Ponnaiah
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Sabarinathan Ramasamy
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Saravanakumar Velusamy
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Manoj Vasant Murhekar
Indian Council of Medical Research (ICMR), National Institute of Epidemiology, Chennai 600077, India
Subash Babu
International Center for Excellence in Research, Indian Council of Medical Research (ICMR), National Institute for Research in Tuberculosis, Chennai 600031, India
Background: Examination of CD4+ T cell responses during the natural course of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection offers useful information for the improvement of vaccination strategies against this virus and the protective effect of these T cells. Methods: We characterized the SARS-CoV-2-specific CD4+ T cell activation marker, multifunctional cytokine and cytotoxic marker expression in recovered coronavirus disease 2019 (COVID-19) individuals. Results: CD4+ T-cell responses in late convalescent (>6 months of diagnosis) individuals are characterized by elevated frequencies of activated as well as mono, dual- and multi-functional Th1 and Th17 CD4+ T cells in comparison to early convalescent (+ T cells were also enhanced in late convalescent compared to early convalescent individuals. Conclusion: Our findings from a low-to middle-income country suggest protective adaptive immune responses following natural infection of SARS-CoV-2 are elevated even at six months following initial symptoms, indicating the CD4+ T cell mediated immune protection lasts for six months or more in natural infection.
