Fig. 3.

CMT167 subcutaneous tumors induce a T-cell response that is skewed toward CD8+ T cells and are less sensitive than CMT167 orthotopic tumors to anti-PD-1/PD-L1 therapy. (A) CMT167 subcutaneous tumor-bearing mice were injected with anti-PD-1, anti-PD-L1, or isotype control antibody (n = 10 for IgG2a and anti-PD-1 groups, n = 5 for IgG2b and anti-PD-L1 groups). CMT167 orthotopic tumor-bearing lungs (n = 9) and CMT167 subcutaneous tumors (n = 7) were analyzed by flow cytometry for (B) CD8⁺ T cells, (C) CD4⁺ T cells, (D) CD4:CD8 ratio, (E) PD-1 expression on CD8⁺ T cells, (F) PD-1 expression on CD4⁺ T cells, and (G) Foxp3 expression in CD4⁺ T cells. Statistically significant differences are indicated as determined by Student unpaired t test; ** = P < 0.01, *** = P < 0.001. (H) PD-L1 expression was analyzed by flow cytometry in CMT167 subcutaneous tumors. Similar results were obtained in five independent mice.