FIGURE 10.
In vivo effect of trans-presented IL-15 and encapsulated antigen in a melanoma model. To test the adjuvant effects of surface-presented IL-15:IL-15Rα in vivo, we used a B16 melanoma model. a, C57Bl/6 mice were injected intravenously with 1 × 105 OVA-expressing B16 melanoma cells (B16-OVA) to establish pulmonary tumor nodules (n = 5 mice/group). 1 day, 2 days, and 10 days after B16-OVA inoculation, mice were injected intraperitoneally with different IL-15:IL-15Rα constructs. Mice were sacrificed upon signs of pulmonary distress. Survival curves were compared against the negative control (PBS) using the Mantel-Cox test. ** indicates a significance level of p ≤ 0.01, and * indicates p ≤ 0.05. b, to test the effect of IL-15 configuration, mice were inoculated subcutaneously with 0.5 × 106 OVA-expressing B16 melanoma cells. Doses of nanoparticle or IL-15 constructs were injected intraperitoneally on days 1, 3, 5, 7, and 14 after tumors reached a minimum diameter of 4 mm. Arrows indicate treatment times (n = 6 mice/group). Tumors were measured every other day, and mice were sacrificed when tumors exceeded 15 mm in greatest diameter. Survival curves were compared by Mantel-Cox and Gehan-Breslow-Wilcoxon analysis. Survival curves were compared against the negative control (NP only) using the Mantel-Cox test. ** indicates a significance level of p ≤ 0.01 for the IL-15:IL-15Ra/NP/OVA group.