RESEARCH ARTICLE

Anti-viral memory T cell responses in the absence of IgG production in a COVID-19 convalescent individual

¹ Institute for Immunology and School of Medicine, Tsinghua University, Beijing 100084, China
² Center for Human Disease Immuno-monitoring, Beijing Friendship Hospital, Beijing 100050, China
³ Department of Hematology, Chui Yang Liu Hospital Affiliated to Tsinghua University, Beijing 100022, China
⁴ Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China
⁵ Department of Cardiology,Chui Yang Liu Hospital Affiliated to Tsinghua University, Beijing 100022, China
⁶ Shanghai Immune Therapy Institute, Shanghai Jiaotong University School of Medicine-affiliated Renji Hospital, Shanghai 200127, China

^* Corresponding authors (emails: chendong@tsinghua.edu.cn (Chen Dong); lingni@tsinghua.edu.cn (Ling Ni); anzhenchenfang@163.com (Fang Chen))

Received: 11 November 2021
Revised: 17 December 2021
Accepted: 27 December 2021

Abstract

Cellular and humoral immunity are both important in host defense against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although defects in SARS-CoV-2-specific T cell immunity have been found in patients with severe lung pathology, it is still largely unclear whether virus-specific T cells are sufficient for host protection. Here, we found that in a previously characterized cohort of convalescent subjects, one individual, though lacking detectable anti-viral neutralizing IgG antibodies, showed virus-specific T cell responses, both in CD4⁺ and CD8⁺ T cells. SARS-CoV-2-specific T cells in this and other individuals are maintained for up to 10 months. This study thus further supports a critical role of T cells in host defense against SARS-CoV-2, offering new insights into the design and evaluation of COVID-19 vaccines.