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Kinetics and Durability of Antibody and T-Cell Responses to SARS-CoV-2 in Children
Megan A Files1, Lauren Gentles2, Leanne Kehoe3
1Department of Medicine, School of Medicine, University of Washington, Seattle, Washington.
Insights
Children show durable T-cell immunity to SARS-CoV-2 spike protein after COVID-19, unlike declining antibody responses to the nucleocapsid protein. This age-independent immunity offers lasting protection.
Area of Science:
- Immunology
- Virology
- Pediatrics
Background:
- T-cell responses to SARS-CoV-2 in children are not well understood.
- Limited data exists on the kinetics and durability of these responses post-COVID-19.
Purpose of the Study:
- To characterize T-cell and antibody responses to SARS-CoV-2.
- To compare these responses over time and across different age groups in children.
Main Methods:
- Studied a cohort of children (6 months to 20 years) with COVID-19.
- Archived peripheral blood mononuclear cells and sera at 1, 6, and 12 months post-symptom onset.
- Compared antibody and T-cell responses to nucleocapsid (N) and spike (S) proteins across four age strata.
Main Results:
- Antibody responses to N declined significantly by 1 year post-infection.
- Functional breadth of CD4+ T-cell responses to N also decreased over time.
- CD4+ T-cell responses to S were stable, broader than N-specific responses, and similar across age groups.
Conclusions:
- Children develop durable, age-independent T-cell immunity to SARS-CoV-2 structural proteins (S).
- Spike (S)-specific antibody responses were also more durable compared to nucleocapsid (N)-specific antibodies.
Background:
The kinetics and durability of T-cell responses to SARS-CoV-2 in children are not well characterized. We studied a cohort of children aged 6 months to 20 years with COVID-19 in whom peripheral blood mononuclear cells and sera were archived at approximately 1, 6, and 12 months after symptom onset.
Methods:
We compared antibody responses (n = 85) and T-cell responses (n = 30) to nucleocapsid (N) and spike (S) glycoprotein over time across 4 age strata: 6 months to 5 years and 5-9, 10-14, and 15-20 years.
Results:
N-specific antibody responses declined over time, becoming undetectable in 26 (81%) of 32 children by approximately 1 year postinfection. Functional breadth of anti-N CD4+ T-cell responses also declined over time and were positively correlated with N-antibody responses (Pearson r = .31, P = .008). CD4+ T-cell responses to S displayed greater functional breadth than N in unvaccinated children and, with neutralization titers, were stable over time and similar across age strata. Functional profiles of CD4+ T-cell responses against S were not significantly modulated by vaccination.
Conclusions:
Our data reveal durable age-independent T-cell immunity to SARS-CoV-2 structural proteins in children over time following COVID-19 infection as well as S-antibody responses in comparison with declining antibody responses to N.
