Figure 5.

circBART2.2 regulates PD-L1 expression through binding to RIG-I. A, PD-L1 expression was examined in HONE1 and HK1 cells after circBART2.2 overexpression or knockdown of RIG-I simultaneously using RT-PCR or Western blotting. B, PD-L1 expression was examined in HONE1-EBV and HK1-EBV cells after circBART2.2 knockdown and RIG-I activator 5′-ppp-dsRNA treatment using RT-PCR or Western blotting. C, The expression of PD-L1 was measured in HONE1 and HK1 cells after circBART2.2 overexpression and simultaneous RIG-I knockdown or HONE1-EBV and HK1-EBV cells after circBART2.2 knockdown and simultaneous RIG-I activator 5′-ppp-dsRNA treatment by flow-cytometric analysis using anti–PD-L1 antibody. Each experiment was independently repeated three times; the original results are shown in Supplementary Fig. S6C. MFI, mean fluorescence intensity. D, Annexin V⁺ PI⁺ cells of CD8-positive active T cells were measured by flow cytometry in T cells cocultured with EBV-negative HONE1 and HK1cells after circBART2.2 overexpression or knockdown of RIG-I simultaneously. Each experiment was independently repeated three times; the original results are shown in Supplementary Fig. S7B. E, Proportions of CD8-positive active T cells were measured by flow cytometry in T cells cocultured with HONE1-EBV and HK1-EBV cells after circBART2.2 knockdown and simultaneous RIG-I activator 5′-ppp-dsRNA treatment. Each experiment was independently repeated three times; the original results are shown in Supplementary Fig. S7C. NS, not significant; ***, P < 0.001.