Fig. 1. Comparison of SARS-CoV-2 RBD-specific antibodies and
SARS-CoV-2-specific T cell response in healthy controls and recovered
children and adolescents. (A) Serological responses to recombinant RBD
protein in 31 recovered COVID-19 patients with median 46.5 recovery days
and ranging 29-219 days and 20 uninfected controls. Dash line indicated
the anti-RBD IgG ratio reference obtained from uninfected controls. (B)
Representative data of the T cell response towards SARS-CoV-2 peptide
pools in controls and recovered patients. (C) Immunophenotyping of PBMCs
for frequency of CD4+, CD8+, or CD69+ T cells, IFN-γ+ cells, and
CD69+/IFN-γ+ double-positive cells from uninfected individuals (n=20) or
convalescent children and adolescents (n=31). Data are presented as
mean±SD and analyzed using two-sided Student’s t-test between control
and patient groups. *p<0.05, **p<0.01,
***p<0.001
Fig. 2. Measurement of SARS-CoV-2-specific T cell
response in recovered patients. Total T cell responses towards
SARS-CoV-2 Membrane (M), Nuclear (N) and Spike (S) peptides and mixed
peptide pools in stacked columns representing the summation of different
measured immune subsets in CD4+ and CD8+ T cells after 16 hours of
incubation of PBMCs from recovered patient. Data are expressed as
mean±SD. Dash line in the stack columns indicated the corresponding
reference CD4+ and CD8+ T cells response stimulated by different
SARS-CoV-2 peptide in uninfected controls group.
Fig. 3. SARS-CoV-2-specific RBD and T cell responses over time.(A) Regression analysis of the measured RBD IgG ratio in convalescent
serum was plotted against the post-infection time. The best fitting
trendline is shown. The calculated t1/2 was 121.6 days
and the estimated duration of antibodies was 7.9 months compared with
the average basal level obtained from uninfected individuals. (B)
Representative T cell subset frequencies in PBMC of recovered patients
were plotted against the post-infection period showing a flat slope for
(i) CD4+ and (ii) CD8+, indicating a sustained T cell response to
SARS-CoV-2 virus in recovered pediatric patients.
Fig. 4. Age-dependent differences of SARS-CoV-2-specific S-RBD
IgG level and SARS-CoV-2-specific T cell response in recovered children
and adolescents . The corresponding reference anti-RBD IgG ratio and T
cell response obtained from uninfected control was indicated as a dash
line in the figures. (A) Serological analysis in 15 patients who were
younger than 12 years and 16 patients who were 12 years or older. Data
was adjusted by recovery days and comparisons analyzed by two-sided
Student’s t-test *p<0.05. (B) Comparison analysis of the total
measured CD4+ T cell responses to (i)mixed peptide pools and (ii) S
peptide between younger children and older children. (C) Comparison
analysis of the total measured CD8+ T cell responses to (i)mixed peptide
pools and (ii)S peptide between younger children and older children. (D)
Correlation analysis of anti-RBD IgG level against (i) CD4+ and (ii)
CD8+ T cells response in the recovery patients. Data was plotted as
age-subgroups with color-labelled dots in the scattered plots. A
trendline indicated the correlations direction of the analysis
parameters.