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

Ling Ni,Meng-Li Cheng,Chen Dong,Fang Chen,Yazheng Yang,Cheng-Feng Qin,Yu Feng,Gengzhen Zhu,Xiaoli Li,Ruifeng Li,Fang Ye,Hui Zhao,Li-Nan Zhang,Qin Qiao,Xuan Zhong

doi:10.1051/nso/2021003

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.

Highlights

The current global pandemic of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1], is affecting many countries all over the world
We still did not observe S-receptor binding domain (RBD) or nucleocapsid protein (NP)-specific IgG in the serum of c#9 at the 2nd follow-up, but her levels of total IgG were similar to other convalescent subjects and healthy donors
Our results indicate that memory SARS-CoV-2-specific T cells could persist for months after infection in a majority of recovered subjects

Summary

Introduction

The current global pandemic of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1], is affecting many countries all over the world. The adaptive immune system plays a key role in controlling viral infection. There has been rapid progress in understanding adaptive immunity to SARS-CoV-2. Less than two months after declaration of a global pandemic on March 11, 2020, we and other groups reported the detection of anti-SARS-CoV-2 antibodies and T cells in convalescent individuals [2,3,4]. Grifoni et al [3] found that nearly 70% and 100% of COVID-19 recovered patients mounted SARS-CoV-2-specific CD8+ and CD4+ T cell responses, respectively, while a report by Wu et al[4] showed that ~94% of COVID-

Methods

Results

Conclusion