Fig. 5.

TTFields in combination with anti-PD-1 are therapeutically effective in murine lung cancer model. Ten-12-week-old male C57Bl/6 mice were injected directly into the lungs with Lewis lung carcinoma (LLC-1; 3 × 10³ cells). a Application of TTFields to the mouse lungs was initiated 6 days afterward and was maintained for 7 days. Mice received an I.P. injection of anti-PD-1 (αPD-1) or Rat IgG2a, as indicated in the scheme. b At the end of the experiment, tumor volume was measured using Vernier calipers. N = 3, and the results are reported as mean ± SD of three pooled independent experiments with total of 5–8 mice per group. Tumors were harvested and analyzed for the percentages (c–e) and PD-L1 expression levels (f–h) of tumor (c, f) CD45+ cells, d, g dendritic cells (CD45+CD11c+), e, h macrophages (CD45+CD11b+F4/80+) using flow cytometry. Percentages of i CD3+CD8+, j CD3+CD4+, and k Foxp3+CD3+CD4+TILs. l, m TILs were harvested from LLC-1 tumor-bearing mice and stimulated with anti-CD3 and anti-CD28 before intracytoplasmic cytokine staining. Expression levels of IFN-γ+in CD3+CD8+ (l) and CD3+CD4+ (m). N = 2, and bars indicate mean of two pooled independent experiment with 5–8 mice per group. Each circle represents one mouse. P values were determined using the Kruskal–Wallis test followed by a Dunn’s post-test for (b) or unpaired two-tailed t test for (c–m). *P < 0.05; **P < 0.01; ***P < 0.001. MFI Median fluorescence intensity