Figure 4.

Checkpoint protein positivity of splenocytes by immune cell type after shIDO-ST treatment. Mice with LLC1 tumors (average 80 mm³) were treated with three consecutive doses of 1 × 10⁶ cfu of shScr-ST or shIDO-ST and spleens were processed for flow cytometry 48 h after the third treatment. n = 3 mice per group. Cells were gated by CD45 positivity and then by cell type (CD4⁺, CD8⁺, CD11c⁺, CD11b⁺F4/80⁺, CD11b⁺Ly6C⁺, CD11b⁺Ly6G⁺, and CD3^-NK1.1⁺). Flow cytometry is represented by histogram overlay followed by bar graph quantification of histogram results. (A) Frequency of PD-L1⁺ cells by immune cell type. (B) Frequency of PD-1⁺ cells by immune cell type. (C) Frequency of CTLA-4⁺ cells by immune cell type. (A–C) * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001.