TY - JOUR T1 - Age-related Differences in Immune Reactions to SARS-CoV-2 Spike and Nucleocapsid Antigens JF - In Vivo JO - In Vivo SP - 70 LP - 78 DO - 10.21873/invivo.13055 VL - 37 IS - 1 AU - PATRICK MORHART AU - SVEN KEHL AU - WOLFGANG SCHUH AU - KATHARINA HERMES AU - STEFAN MELTENDORF AU - ANTJE NEUBERT AU - MICHAEL SCHNEIDER AU - MONIKA BRUNNER-WEINZIERL AU - HOLM SCHNEIDER AU - HOLGER LINGEL Y1 - 2023/01/01 UR - http://iv.iiarjournals.org/content/37/1/70.abstract N2 - Background/Aim: The manifestation and severity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections show a clear correlation to the age of a patient. The younger a person, the less likely the infection results in significant illness. To explore the immunological characteristics behind this phenomenon, we studied the course of SARS-CoV-2 infections in 11 households, including 8 children and 6 infants/neonates of women who got infected with SARS-CoV-2 during pregnancy. Materials and Methods: We investigated the immune responses of peripheral blood mononuclear cells (PBMCs), umbilical cord blood mononuclear cells (UCBCs), and T cells against spike and nucleocapsid antigens of SARS-COV-2 by flow cytometry and cytokine secretion assays. Results: Upon peptide stimulation, UCBC from neonates showed a strongly reduced IFN-γ production, as well as lower levels of IL-5, IL-13, and TNF-α alongside with decreased frequencies of surface CD137/PD-1 co-expressing CD4+ and CD+8 T cells compared with adult PBMCs. The PBMC response of older children instead was characterized by elevated frequencies of IFN-γ+ CD4+ T cells, but significantly lower levels of multiple cytokines (IL-5, IL-6, IL-9, IL-10, IL-17A, and TNF-α) and a marked shift of the CD4+/CD8+ T-cell ratio towards CD8+ T cells in comparison to adults. Conclusion: The increased severity of SARS-CoV-2 infections in adults could result from the strong cytokine production and lower potential to immunomodulate the excessive inflammation, while the limited IFN-γ production of responding T cells in infants/neonates and the additional higher frequencies of CD8+ T cells in older children may provide advantages during the course of a SARS-CoV-2 infection. ER -