Anti-PD-L1 treatment reduces exhaustion marker expression on tumour-specific CD8⁺ T cells.

<p>A-G) B16.mOVA cells (10⁵) were injected s.c. to 11c.OVA mice and 3 days later OT-I Tcm-phenotype cells (5 x 10⁶) transferred i.v. OT-I recipients were injected on the day of OT-I transfer and every subsequent 3 days with isotype control or αPD-L1 mAb as indicated. Twelve days after OT-I Tcm-phenotype cells transfer, spleen, tumour draining LN (TDLN), and tumour sites were harvested for flow-cytometric analysis. A) PD-L1 expression was determined in tumour, spleen and TDLN (A) gated on the total bulk population for isotype control mAb-injected (solid line) mice. Isotype-control staining of tumour is shown (dashed line). B, C) the proportion of DC expressing PD-L1 (B) and PD-L1 expression level on DC (C) was determined (gated on CD11c⁺I-A^b+ DC). CD62L and CD44 (D), PD-1 (E, F) and LAG-3 (G) expression was determined on OT-I T cells in spleen, TDLN and tumour. Data are representative of 3 mice/group in 2 separate experiments (A) or individual mice pooled from 2 separate experiments of 2–3 mice per group (B-G) except TDLN in (B, C) which is 3 mice from a single experiment of the 2 performed.