CD19 and neoplasm: Flow cytometric analysis of MC38 tumor-infiltrating immune cells showed an increased accumulation of CD8+ T cells, but not CD4+ T cells, NK1.1+, or CD19+ cells in the Rig-I–/– mice compared with their WT littermates (Figure 1, C–E, and Supplemental Figure 1G), which was verified by IHC analysis of tumor-infiltrating T cells (Figure 1, F and G).