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Front Immunol
. 2021 Jul 12;12:687449.
doi: 10.3389/fimmu.2021.687449. eCollection 2021.
Reactive T Cells in Convalescent COVID-19 Patients With Negative SARS-CoV-2 Antibody Serology
Sophie Steiner 1 , Tatjana Schwarz 2 3 , Victor M Corman 2 3 , Franziska Sotzny 1 , Sandra Bauer 1 , Christian Drosten 2 3 , Hans-Dieter Volk 1 4 5 , Carmen Scheibenbogen 1 4 , Leif G Hanitsch 1
Affiliations
- PMID: 34322120
- PMCID: PMC8312095
- DOI: 10.3389/fimmu.2021.687449
Abstract
Despite RT-PCR confirmed COVID-19, specific antibodies to SARS-CoV-2 spike are undetectable in serum in approximately 10% of convalescent patients after mild disease course. This raises the question of induction and persistence of SARS-CoV-2-reactive T cells in these convalescent individuals. Using flow cytometry, we assessed specific SARS-CoV-2 and human endemic coronaviruses (HCoV-229E, -OC43) reactive T cells after stimulation with spike and nucleocapsid peptide pools and analyzed cytokine polyfunctionality (IFNγ, TNFα, and IL-2) in seropositive and seronegative convalescent COVID-19 patients as well as in unexposed healthy controls. Stimulation with SARS-CoV-2 spike and nucleocapsid (NCAP) as well as HCoV spike peptide pools elicited a similar T cell response in seropositive and seronegative post COVID-19 patients. Significantly higher frequencies of polyfunctional cytokine nucleocapsid reactive CD4+ T cells (triple positive for IFNγ, TNFα, and IL-2) were observed in both, seropositive (p = 0.008) and seronegative (p = 0.04), COVID-19 convalescent compared to healthy controls and were detectable up to day 162 post RT-PCR positivity in seronegative convalescents. Our data indicate an important role of NCAP-specific T cells for viral control.
Keywords: T cell response; antibody response; coronavirus disease 2019 (COVID-19); human endemic coronavirus 229E (HCoV-229E); human endemic coronavirus OC43 (HCoV-OC43); seronegative; severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).