Fig 1: Long-term persistence of SARS-CoV-2-specific CD8+ T cells in individuals with mild COVID-19 and asymptomatic seropositive individuals(A) Schematic overview of the in vitro expansion protocol for detection of CD8+ T cell responses.(B and C) 5 × 106 PBMCs were treated as described in (A). Depicted are representative raw data (B) and quantification (C) of IFN-γ-releasing T cells upon 9-mer peptide pool re-stimulation after expansion. Responders were identified respective to the non-stimulated negative control (detection limit set to 0.1% IFN-γ+ CD8+/CD8− T cells after background subtraction). Data are depicted in a box and whiskers plot - min to max, all points shown. The box extends from the 25th to 75th percentiles, and the middle line indicates the median value. Statistical analyses were performed via one-way ANOVA with Kruskal-Wallis test (∗p < 0.05, ∗∗∗p < 0.001, ∗∗∗∗p <0.0001).(D–G) SARS-CoV-2-specific IgG and CD8+ T cells were measured for individuals with mild COVID-19 (red) and asymptomatic seropositive (blue) individuals at their first follow-up visit (62.4 ± 20.4 days after PCR-confirmed infection and 102.6 ± 24.5 days after study enrollment, respectively) (D), throughout the observation period (connected lines indicate different time points for the same individual) (E and F), and 1 year after PCR-confirmed infection (G). In (G), data are depicted in a box and whiskers plot - min to max, all points shown. The box extends from the 25th to 75th percentiles, and the middle line indicates the median value. For flow cytometry analyses, reactive cells were pre-gated on CD3+ living lymphocytes.