Fig. 4

SARS-CoV-2 infection-induced apoptosis in T cells. a Detection of apoptotic T lymphocytes in human PBCs. PBCs were prepared from COVID-19 patients or from healthy donors. Apoptosis in virally infected T lymphocytes were determined using CD3, SARS-CoV-2 NP antibodies, and TUNEL assay. Detection results for two patients and one healthy donor, or the statistics of apoptotic cells or TUNEL/NP double-positive cells were shown for healthy donors (H, n = 3) or patients (P, n = 5). Comparison of mean values between two groups was analyzed by Student’s t test. *P < 0.05. b Unactivated or activated primary T cells were infected with SARS-CoV-2 (MOI = 0.01) for 8 h and cell apoptosis was analyzed with TUNEL assay. **P < 0.01. c Activated Jurkat cells were infected with SARS-CoV-2 (MOI = 0.01) for 0, 24, 48, and 72 h. The ratio of apoptotic cells in 72 h mock or SARS-CoV-2-infected cells were shown (flow chart). The ratio of apoptotic cells in different time points were also compared (plot). d Samples from C were subjected for RNA-seq analysis. The top ten upregulated GO pathways in 48 h compared to 24 h group are shown. Heatmap shows the normalized expression of genes that were enriched from PID HIF1 pathway. The data were analyzed by Student’s t test (*P < 0.05; **P < 0.01; NS no significance). e Compared to healthy donors, differentially expressed genes of severe COVID-19 patients were shown in the volcano plot, and the top ten differential expressed pathways were shown in the right panel