Early induction of functional SARS-CoV-2 specific T cells associates with rapid viral clearance and mild disease in COVID-19 patients

Tan, Anthony T.; Linster, Martin; Tan, Chee Wah; Le Bert, Nina; Chia, Wan Ni; Kunasegaran, Kamini; Zhuang, Yan; Tham, Christine Y.L.; Chia, Adeline; Smith, Gavin JD.; Young, Barnaby; Kalimuddin, Shirin; Low, Jenny G.H.; Lye, David; Wang, Lin-Fa; Bertoletti, Antonio

Virus-specific humoral and cellular immunity act synergistically to protect the host from viral infection. We interrogate the dynamic changes of virological and immunological parameters in 12 patients with symptomatic acute SARS-CoV-2 infection from disease onset to convalescence or death. We quantify SARS-CoV-2 viral RNA in the respiratory tract in parallel with antibodies and circulating T cells specific for various structural (NP, M, ORF3a and spike) and non-structural proteins (ORF7/8, NSP7 and NSP13). While rapid induction and quantity of humoral responses associates with an increase in disease severity, early induction of IFN-γ secreting SARS-CoV-2 specific T cells is present in patients with mild disease and accelerated viral clearance. These findings provide support for the prognostic value of early functional SARS-CoV-2 specific T cells with important implications in vaccine design and immune monitoring.