In vivo PD-1 blockade increases the expansion of IL-4gfp⁺ T cells within the tLN immediately post-treatment.

<p><i>L. sigmodontis</i>-infected BALB/c IL-4gfp reporter mice were treated with a blocking anti-PD-1 mAb (closed triangles) or rat IgG (closed squares) from d 28–37 and IL-4gfp⁺ T cells from the PC (A–D) and tLN (E–H) analysed at d 40. The proportion (A & E) and total number (B & F) of CD4⁺ T cells expressing GFP, as well as the percentage of IL-4gfp⁺ Th2 cells producing IL-4 (C & G) and IL-5 (D & H) protein following simulation with PMA and ionomycin was assessed. Panels show one representative experiment of three with 4–6 mice per group. Symbols denote individual mice and lines represent means. *** Significant effect of infection independent of treatment (p<0.001, ANOVA performed on combined data from three independent experiments). ¶ Significant pair-wise comparison (p<0.05, Tukey's HSD).