Fig. 1. Emergence of immune responses during non-severe symptomatic COVID-19.

a, Timeline of COVID-19, showing detection of SARS-CoV-2 in sputum, nasopharyngeal aspirates and feces but not urine, rectal swab or whole blood. SARS-CoV-2 was quantified by rRT-PCR; cycle threshold (Ct) is shown. A higher Ct value means lower viral load. Dashed horizontal line indicates limit of detection (LOD) threshold (Ct = 45). Open circles, undetectable SARS-CoV-2. b, Anteroposterior chest radiographs on days 5 and 10 following symptom onset, showing radiological improvement from hospital admission to discharge. c, Immunofluorescence antibody staining, repeated twice in duplicate, for detection of IgG and IgM bound to SARS-CoV-2-infected Vero cells, assessed with plasma (diluted 1:20) obtained at days 7–9 and 20 following symptom onset. d–f, Frequency (left set of plots) of CD27^hiCD38^hi ASCs (gated on CD3^–CD19⁺ lymphocytes) and activated ICOS⁺PD-1⁺ T_FH cells (gated on CD4⁺CXCR5⁺ lymphocytes) (d), activated CD38⁺HLA-DR⁺ CD8⁺ or CD4⁺ T cells (e), and CD14⁺CD16⁺ monocytes and activated HLA-DR⁺ natural killer (NK) cells (gated on CD3^–CD14^–CD56⁺ cells) (f), detected by flow cytometry of blood collected at days 7–9 and 20 following symptom onset in the patient and in healthy donors (n = 5; median with interquartile range); gating examples at right. Bottom right histograms and line graphs, staining of granzyme A (GZMA (A)), granzyme B (GZMB (B)), granzyme K (GZMK (K)), granzyme M (GZMM (M)) and perforin (Prf) in parent CD8⁺ and CD4⁺ T cells and activated CD38⁺HLA-DR⁺ CD8⁺ and CD4⁺ T cells. Gating and experimental details are in Extended Data Fig. 3.

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