Robust T cell immunity in convalescents with asymptomatic or mild COVID-19

Takuya Sekine1,13, André Perez-Potti1,13, Olga Rivera-Ballesteros1,13, Kristoffer Strålin2, Jean-Baptiste Gorin1, Annika Olsson2, Sian Llewellyn-Lacey3, Habiba Kamal2, Gordana Bogdanovic4, Sandra Muschiol4, David J. Wullimann1, Tobias Kammann1, Johanna Emgård1, Tiphaine Parrot1, Elin Folkesson2, Olav Rooyackers5,6, Lars I. Eriksson6,7, Anders Sönnerborg2,8, Tobias Allander4,9, Jan Albert4,9, Morten Nielsen10,11, Jonas Klingström1, Sara Gredmark-Russ1,2, Niklas K. Björkström1, Johan K. Sandberg1, David A. Price3,12, Hans-Gustaf Ljunggren1,13, Soo Aleman2,13, Marcus Buggert1,13,14; Karolinska COVID-19 Study Group

1Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden. 2Division of Infectious Diseases, Karolinska University Hospital and Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden. 3Division of Infection and Immunity, Cardiff University School of Medicine, University Hospital of Wales, Cardiff, UK 5Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden. 5Department of Clinical Interventions and Technology, Karolinska Institutet, Stockholm, Sweden. 6Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden. 7Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden. 8Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden. 9Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden. 10Department of Health Technology, Technical University of Denmark, DK-2800 Lyngby, Denmark. 11Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, San Martín, Argentina.

12Systems Immunity Research Institute, Cardiff University School of Medicine, University Hospital of Wales, Cardiff, UK
13Equal contribution
14Lead contact
Lead contact: Marcus Buggert, PhD, Karolinska Institutet, Alfred Nobels Allé 8, 141 52 Stockholm, Sweden. Email: marcus.buggert@ki.se. Tel: +46-739245224.

One sentence summary SARS-CoV-2 induces robust memory T cell responses in antibody-seronegative and antibody-seropositive individuals with asymptomatic or mild COVID-19.

ABSTRACT SARS-CoV-2-specific memory T cells will likely prove critical for long-term immune protection against COVID-19. We systematically mapped the functional and phenotypic landscape of SARS-CoV-2-specific T cell responses in a large cohort of unexposed individuals as well as exposed family members and individuals with acute or convalescent COVID-19. Acute phase SARS-CoV-2-specific T cells displayed a highly activated cytotoxic phenotype that correlated with various clinical markers of disease severity, whereas convalescent phase SARS-CoV-2-specific T cells were polyfunctional and displayed a stem-like memory phenotype. Importantly, SARS-CoV2-specific T cells were detectable in antibody-seronegative family members and individuals with a history of asymptomatic or mild COVID-19. Our collective dataset shows that SARS-CoV-2 elicits robust memory T cell responses akin to those observed in the context of successful vaccines, suggesting that natural exposure or infection may prevent recurrent episodes of severe COVID-19 also in seronegative individuals.

https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1.full.pdf