Figure 2.

EAE outcome in animals treated with PD-1 pathway blockade. The disease scores for control and anti–PD-1–treated animals >40 d of follow up are shown, for WT mice with early therapy (a) and delayed therapy (b), and for CD28-deficient mice (d). There is a highly significant difference in disease severity between the early therapy and control groups (P = 0.0053 for WT and P = 0.0074 for CD28-deficient mice by two-tailed Mann-Whitney U test). No difference was found with delayed therapy. PD-L2 blockade also augmented disease (P = 0.03 compared with control by two-tailed Mann-Whitney U test) whereas PD-L1 blockade had no effect (c).