Poly I:C immunotherapy increases the proportion of intratumoral CD8⁺IFNγ⁺ T cells in C57BL/6 and PLT2 mice.

C57BL/6 (WT) and PLT2 mice were challenged with B16 tumor cells and treated with peri-tumoral injections of PBS or Poly I:C on day 9, 11, 13 and 15. On day 17, tumor-dLN and tumors were removed for flow cytometry analysis. (A) Total numbers of CD8+ T cells in dLN and tumors. (B) Representative flow plots showing the proportion of IFNγ+ cells in the intratumoral CD8+ T cell population as determined by intracellular cytokine staining. (C) Proportions of CD8+IFNγ+ cells in tumors, expressed as percentage of the CD45+ population. Bar graphs show mean+SEM for pooled data from 2–5 independent experiments, each with 4–5 mice/group, that gave similar results. Each dot refers to one mouse. Statistical analysis was by two-way ANOVA with Bonferroni’s post-test. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001.