Figure 1
Expression of ICOS on T cell subsets in the blood and tumor following radiation. (a) (i) Experimental design. 2 × 105 CT26 cells were implanted subcutaneously into the flanks of Balb/c mice on day 0. Half of the mice received 12 Gy radiation to the tumor using CT guided radiation therapy on day 14. On day 7 (prior to administering radiation), day 15 (24 h post radiation) and day 21 (7 days post radiation) blood was harvested for flow analysis. On day 21 animals were sacrificed and tumors were harvested for flow analysis. (ii) Representative flow plots showing gating strategy for immune cell populations. (b) Quantitative dot plot of percent ICOS expression on CD8+, CD4+CD25+(Treg), and CD4+CD25−, in whole blood over time with and without radiation. (c) Quantitative dot plots of percent ICOS expression on CD8+, CD4+FoxP3+(Treg), CD4+and in tumors on day 21 with and without radiation. In all graphs, bar represents mean, Error bars SEM, ****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05 as determined by unpaired student t test. N = 5 mice per group and experiments were repeated at least 2x.
