FIGURE 6.

Removal of tumor‐associated macrophages (TAMs) by clodronate liposome (CL) cancels anti‐PD‐L1 Ab resistance in IL4I1‐overexpressing tumors. (A) RT‐qPCR measurement of CCL2 and CCL10 expression. (B) Treatment schedule. The CL‐treated group received the first CL administration before cell transplantation. Following grouping into CL administration (12.5 mg/kg) and control liposome groups, mice were transplanted with Mock or IL4I1‐overexpressing B16‐F10 tumor cells. Subsequently, the groups were divided into anti‐PD‐L1 Ab treatment (5 mg/kg) and IgG control groups. Tumor measurements were taken over time for a total of eight groups (n = 5). (C) Quantitation of CD68⁺ TAMs per weight of the tumor treated with CL (12.5 mg/kg) or control liposome using flow cytometry analysis at day 0 in (B) (n = 3 mice per group). (D) Dot plot showing the differences in tumor volume at day 6 of anti‐PD‐L1 Ab treatment in individual animals. Lines indicate median values. (E) Quantitation of CD8⁺ T cells per weight of the tumor using flow cytometry analysis at day 13 in (B) (n = 3 mice per group). Data are expressed as means ± SEM, and analyzed by one‐way ANOVA with Tukey's multiple comparisons (A, C–E). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. ns, not statistically significant.