AUTHOR=Lima Karina , Fontoura Julia C. , de Souza Priscila Oliveira , Fazolo Tiago , Hilario Gabriel , Zorzetto Renata , Rodrigues Junior Luiz C , Coimbra Lais D. , Borin Alexandre , Bispo-dos-Santos Karina , Granja Fabiana , Marques Rafael Elias , Zavaglia Gabriela Oliveira , Fernandes Ingrid Rodrigues , Varela Fernanda Hammes , Polese-Bonatto Marcia , Tonini Maiko Luís , Ikeda do Carmo Greice Madeleine , de Almeida Walquiria Aparecida Ferreira , Borges Thiago J. , Nakaya Helder I. , Proenca-Modena José Luiz , Callegari-Jacques Sidia Maria , Scotta Marcelo Comerlato , Stein Renato T. , Bonorino Cristina TITLE=SARS-CoV-2 infected children form early immune memory responses dominated by nucleocapsid-specific CD8+ T cells and antibodies JOURNAL=Frontiers in Immunology VOLUME=13 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.1033364 DOI=10.3389/fimmu.2022.1033364 ISSN=1664-3224 ABSTRACT=

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.