Frontiers in Immunology (Jul 2021)

Reactive T Cells in Convalescent COVID-19 Patients With Negative SARS-CoV-2 Antibody Serology

  • Sophie Steiner,
  • Tatjana Schwarz,
  • Tatjana Schwarz,
  • Victor M. Corman,
  • Victor M. Corman,
  • Franziska Sotzny,
  • Sandra Bauer,
  • Christian Drosten,
  • Christian Drosten,
  • Hans-Dieter Volk,
  • Hans-Dieter Volk,
  • Hans-Dieter Volk,
  • Carmen Scheibenbogen,
  • Carmen Scheibenbogen,
  • Leif G. Hanitsch

DOI
https://doi.org/10.3389/fimmu.2021.687449
Journal volume & issue
Vol. 12

Abstract

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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.

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