Figure 7. Human PD-1H blockade confers a synergistic antileukemic effect with human PD-1 blockade.

(A) A humanized AML mouse model to demonstrate a synergistic antileukemia effect of anti–hPD-1 with anti–hPD-1H mAbs. Human myeloid leukemia cells expressing PD-1H (THP1-WT) or not expressing PD-1H (THP1–PD-1H KO) were s.c. injected into NSG mice reconstituted with human peripheral blood mononuclear cells. (B) Tumor volume was assessed on days 2, 6, and 9. Anti–hPD-1 (100 μg) and/or anti–hPD-1H mAbs (100 μg) were injected on day 7. Day 9 tumor volume is represented. Mean tumor volume ± SEM. Error bars represent SEM. n = 5. *P < 0.05; ***P < 0.001; ****P < 0.001. P value determined by 1-way ANOVA.