Figure 6. The combination of VV plus α-PD-L1 treatment enhances infiltration of effector T cells and reduces Treg cells and exhausted CD8⁺ T cells in the TME.

B6 mice were intraperitoneally inoculated with 5 × 10⁵ MC38-luc and treated with VV and/or α-PD-L1 as described. Single cells were made from primary tumours collected from tumour-bearing mice at day 5 post first treatment, blocked with α-CD16/32 Ab and then stained with antibodies against CD45, CD8, CD4, PD-1, ICOS, PD-1, CTLA-4, TIM-3, LAG-3, TIGIT and Foxp3 to determine the quantities of CD8⁺ T cells (a), CD8⁺ T-cell activation (b–d), CD8⁺ T-cell exhaustion (e–h), Treg cells (i), CD8⁺/CD4⁺Foxp3⁺ T cells (j) and CD4⁺Foxp3⁻ T cells (k,l) in the TME. Of note, the anti-PD-L1 antibody clone 10F.9G2 was used for therapy while clone MHI5 was used for subsequent phenotypic analysis. Data were analysed using Student's t-test (*P<0.05; **P<0.01; ***P<0.001).