Figure 5.

Blocking ILC2 PD-1 expression increases TNF-α production and inhibits tumor progression in vivo. (A) A cohort of PD-1^-/- or WT mice was given an intravenous injection of B16 melanoma cells (2.5 x 10⁵) on day 0. On day 14 lungs were digested and percentage of TNF-α⁺ ILC2s was quantified (B). (C) A cohort of Rag2^-/- or Rag2^-/- PD-1^-/- mice were intravenously injected with B16 melanoma (2.5 x 10⁵) cells on day 0. Mice were also intraperitoneally injected with anti-asialo GM1 or isotype every three days. On day 14, mice were euthanized and percentage of TNF-α⁺ ILC2s was quantified (D). (E) A cohort of Rag2^-/- mice were intravenously injected with B16 melanoma cells (2.5 x 10⁵) on day 0. Mice were intraperitoneally injected with anti-asialo GM1 or isotype every three days. Mice were also intraperitoneally injected with PD-1 blocking antibody or isotype (500µg/mouse) every four days. On day 14, mice were euthanized and lung tumor burden per field was assessed and quantified (F). (G) Total number of lung ILC2 cells present on day 14. (H) Representative flow cytometry plots and corresponding quantification of TNF-α⁺ ILC2s present in the lung on day 14. Error bars are the mean ± SEM. Data are representative of 3 individual experiments with n=5. Student’s t-test, NS = Non-statistical, *p < 0.05, **p < 0.01.