Serum neutralizing capacity and T-cell response against the omicron BA.1 variant in seropositive children and their parents one year after SARS-CoV-2 infection

Alina Seidel; Eva-Maria Jacobsen; Dorit Fabricius; Magdalena Class; Maria Zernickel; Carmen Blum; Carina Conzelmann; Tatjana Weil; Rüdiger Groß; Sebastian F N Bode; Hanna Renk; Roland Elling; Maximillian Stich; Frank Kirchhoff; Klaus-Michael Debatin; Jan Münch; Aleš Janda

doi:10.3389/fped.2023.1020865

Serum neutralizing capacity and T-cell response against the omicron BA.1 variant in seropositive children and their parents one year after SARS-CoV-2 infection

Front Pediatr. 2023 Mar 27:11:1020865. doi: 10.3389/fped.2023.1020865. eCollection 2023.

Authors

Alina Seidel¹, Eva-Maria Jacobsen², Dorit Fabricius², Magdalena Class², Maria Zernickel², Carmen Blum², Carina Conzelmann¹, Tatjana Weil¹, Rüdiger Groß¹, Sebastian F N Bode², Hanna Renk³, Roland Elling^{4

5}, Maximillian Stich⁶, Frank Kirchhoff¹, Klaus-Michael Debatin², Jan Münch¹, Aleš Janda²

Affiliations

¹ Ulm University Medical Center, Institute of Molecular Virology, Ulm, Germany.
² Department of Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm University, Ulm, Germany.
³ University Children's Hospital Tuebingen, Tuebingen, Germany.
⁴ Center for Chronic Immunodeficiency (CCI), Medical Center-University of Freiburg, Faculty of Medicine, Institute for Immunodeficiency, University of Freiburg, Freiburg, Germany.
⁵ Center for Pediatrics and Adolescent Medicine, Medical Center, Faculty for Medicine, University of Freiburg, Freiburg, Germany.
⁶ Department of Pediatrics I, University Children's Hospital Heidelberg, Heidelberg, Germany.

Abstract

Introduction: Durability of immune protection against reinfection with SARS-CoV-2 remains enigmatic, especially in the pediatric population and in the context of immune-evading variants of concern. Obviously, this knowledge is required for measures to contain the spread of infection and in selecting rational preventive measures.

Methods: Here, we investigated the serum neutralization capacity of 36 seropositive adults and 34 children approximately one year after infection with the ancestral Wuhan strain of SARS-CoV-2 by using a pseudovirus neutralization assay.

Results: We found that 88.9% of seropositive adult (32/36) and 94.1% of seropositive children (32/34) convalescents retained the neutralizing activity against the SARS-CoV-2 Wuhan strain (WT). Although, the neutralization effect against Omicron BA.1 (B.1.1.529.1) was significantly lower, 70.6% (24/34) of children and 41.7% (15/36) of adults possessed BA.1 cross-neutralizing antibodies. The spike 1 (S1)-specific T cell recall capacity using an activation-induced marker assay was analyzed in 18 adults and 16 children. All participants had detectable S1-specific CD4 T cells against WT, and 72.2% (13/18) adults and 81,3% (13/16) children had detectable S1 WT-specific CD8 T cells. CD4 cross-reactivity against BA.1 was demonstrated in all investigated adults (18/18), and 66.7% (12/18) adult participants had also detectable specific CD8 BA.1 T cells while we detected BA.1 S1 reactive CD4 and CD8 T cells in 81.3% (13/16) children.

Discussion: Together, our findings demonstrate that infection with the ancestral strain of SARS-CoV-2 in children as well as in adults induces robust serological as well as T cell memory responses that persist over at least 12 months. This suggests persistent immunological memory and partial cross-reactivity against Omicron BA.1.

Keywords: SARS-CoV-2; T cells; children; neutralizing antibody; omicron variant; variant of concern.

Grants and funding

This work was financially supported by the Ministry of Science, Research and Arts Baden-Württemberg within the framework of the special funding line for COVID-19 research to the Freiburg, Tübingen, Ulm and Heidelberg centers, and the Federal Ministry of Health to the Freiburg study site (RE), the Federal Ministry for Economic Affairs and Energy on the basis of a decision by the German Bundestag COMBI-COV-2 (JM). JM acknowledges funding by the DFG (CRC 1279) and the Ministerium für Wissenschaft, Forschung und Kunst (Kap. 1499 TG93). FK was supported by DFG grants (CRC 1279, SPP 1923, CEMMMA) and the BMBF (Restrict SARS-CoV-2). RE is supported by the Berta-Ottenstein-Programme for advanced Clinician Scientists, Faculty of Medicine, University of Freiburg. The funders had no role in the study design, data collection, data analysis or the decision to publish.