COVID-19 manifests as a milder disease in children than adults, but the underlying mechanisms are not fully characterized. Here we assess the difference in cellular or humoral immune responses of pediatric and adult COVID-19 patients to see if these factors contribute to the severity dichotomy. Children's non-specific immune profile is dominated by naive lymphocytes and HLA-DRhighCX3CR1low dendritic cells; meanwhile, children show strong specific antibody and T cell responses for viral structural proteins, with their T cell responses differing from adults by having weaker CD8+TNF+ T cells responses to S peptide pool but stronger responses to N and M peptide pools. Finally, viral mRNA is more abundant in pediatric patients. Our data thus support a scenario in which SARS-CoV-2 infected children contribute to transmission yet are less susceptible to COVID-19 symptoms due to strong and differential responses to the virus.
Fazolo T, Lima K, Fontoura JC, de Souza PO, Hilario G, Zorzetto R, Júnior LR, Pscheidt VM, de Castilhos Ferreira Neto J, Haubert AF, Gambin I, Oliveira AC, Mello RS, de Bastos Balbe E Gutierres M, Gassen RB, Coimbra LD, Borin A, Marques RE, Sartor ITS, Zavaglia GO, Fernandes IR, Nakaya HI, Varela FH, Polese-Bonatto M, Borges TJ, Callegari-Jacques SM, da Costa MSC, de Araujo Schwartz J, Scotta MC, Stein RT, Bonorino C
Microbiology or Immunology