Frontiers in Immunology (Nov 2022)

SARS-CoV-2 infected children form early immune memory responses dominated by nucleocapsid-specific CD8+ T cells and antibodies

  • Karina Lima,
  • Julia C. Fontoura,
  • Priscila Oliveira de Souza,
  • Tiago Fazolo,
  • Gabriel Hilario,
  • Renata Zorzetto,
  • Luiz C Rodrigues Junior,
  • Lais D. Coimbra,
  • Alexandre Borin,
  • Karina Bispo-dos-Santos,
  • Fabiana Granja,
  • Fabiana Granja,
  • Rafael Elias Marques,
  • Gabriela Oliveira Zavaglia,
  • Ingrid Rodrigues Fernandes,
  • Fernanda Hammes Varela,
  • Marcia Polese-Bonatto,
  • Maiko Luís Tonini,
  • Greice Madeleine Ikeda do Carmo,
  • Walquiria Aparecida Ferreira de Almeida,
  • Thiago J. Borges,
  • Helder I. Nakaya,
  • José Luiz Proenca-Modena,
  • José Luiz Proenca-Modena,
  • Sidia Maria Callegari-Jacques,
  • Marcelo Comerlato Scotta,
  • Marcelo Comerlato Scotta,
  • Renato T. Stein,
  • Renato T. Stein,
  • Cristina Bonorino,
  • Cristina Bonorino

DOI
https://doi.org/10.3389/fimmu.2022.1033364
Journal volume & issue
Vol. 13

Abstract

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This is the third year of the SARS-CoV-2 pandemic, and yet most children remain unvaccinated. COVID-19 in children manifests as mostly mild or asymptomatic, however high viral titers and strong cellular and humoral responses are observed upon acute infection. It is still unclear how long these responses persist, and if they can protect from re-infection and/or disease severity. Here, we analyzed immune memory responses in a cohort of children and adults with COVID-19. Important differences between children and adults are evident in kinetics and profile of memory responses. Children develop early N-specific cytotoxic T cell responses, that rapidly expand and dominate their immune memory to the virus. Children’s anti-N, but not anti-S, antibody titers increase over time. Neutralization titers correlate with N-specific antibodies and CD8+T cells. However, antibodies generated by infection do not efficiently cross-neutralize variants Gamma or Delta. Our results indicate that mechanisms that protect from disease severity are possibly different from those that protect from reinfection, bringing novel insights for pediatric vaccine design. They also underline the importance of vaccination in children, who remain at risk for COVID-19 despite having been previously infected.

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