VZV-mediated induction of PD-1, PD-L1, PD-L2 and CTLA-4 expression in VZV ORF34- or ORF18-specific CD8⁺ T cells.

VZV ORF34- or ORF18-specific CD8+ T cells were co-cultured with uninfected- or VZV-infected HFLs/HBVAFs for 48 h, harvested and analyzed for VZV-gE, PD-1, PD-L1, PD-L2, CTLA-4, LAG-3 and TIM-3 expression. Live CD8+ cells are shown. (A) Flow cytometry gating strategy for uninfected (UI), VZV gE-negative bystander (Bys) and VZV gE+ (V+) CD8+ T cells. (B) Representative flow cytometry plots of PD-1, PD-L1, PD-L2, CTLA-4, LAG-3 and TIM-3 MFI expression levels. Black histograms = FMO control, grey histograms = UI, blue histograms = Bys and red histograms = V+ cells. (C) Summary of fold change in MFI in PD-1, PD-L1, PD-L2, CTLA-4, LAG-3 and TIM-3 expression levels in: Bys/UI (blue), V+/UI (red) and V+/Bys (red with black stripes) with respect to ORF34- or ORF18-specific CD8+ T cells. Results are representative of 19, 16 and 12 independent experiments for PD-1/PD-L1, PD-L2/CTLA-4 and LAG-3/TIM-3 expression in VZV ORF18-specific CD8+ T cells, respectively, and of 14, 10 and 6 independent experiments for PD-1/PD-L1, PD-L2/CTLA-4 and LAG-3/TIM-3 expression in VZV ORF34-specific CD8+ T cells, respectively. Bar graphs represent average fold-change in MFI ± SEM. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. Statistical significance was determined using RM one-way ANOVA with the Greenhouse-Geisser correction and Tukey posttest.