In vivo PD-1 blockade results in a long-term restoration of Th2 cell functional quality.

<p><i>L. sigmodontis</i>-infected IL-4gfp reporter mice were treated with a blocking anti-PD-1 mAb (closed triangles) or rat IgG (closed squares) from d 28–d43 and Th2 cell quantity and functional quality assessed at d 60. Open symbols represent naïve untreated controls. (A–D) The proportion (A & C) and total number of IL-4gfp⁺ Th2 cells (B & D) in the PC (A & B) and tLN (C & D). Panels show one out of two representative experiments 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 two independent experiments). (E–G) IL-4gfp⁺ Th2 cells were purified from the PC (E & F) and tLN (G) and their ability to proliferate (E) and produce IL-5 (F & G) following in vitro restimulation with LsAg was assessed. Panels show one representative experiment of two. Within each experiment IL-4gfp⁺ Th2 cells were pooled from 6–10 mice per group. Bars show means (E–G). Due to the pooled samples error bars show SD of triplicate cultures for proliferation (E), and there are no error bars or statistics for IL-5 (F & G). ** Significant effect of treatment upon restimulation with LsAg (p<0.01, ANOVA performed using combined data from two independent experiments).