FL3 alone, or in combination with immunotherapy, controls CLL development in vivo. (A-B) Percentage (A) and number (B) of CD19⁺CD5⁺ CLL cells in the peripheral blood (PB) of C57BL/6 mice after adoptive transfer of splenocytes from a sick Eμ-TCL1 mouse, and treated with vehicle (n = 9) or FL3 (n = 8). (C) Survival of mice from panels A-B. (D) Percentage of CLL cells (CD19⁺CD5⁺), B cells (CD19⁺CD5⁻), CD8⁺ T cells (CD3⁺CD8⁺), CD4⁺ T cells (CD3⁺CD4⁺), and Tregs (CD4⁺FOXP3⁺) in the spleen of mice treated with vehicle or FL3, 17 days after adoptive transfer of splenocytes from a sick Eμ-TCL1 mouse (n = 5). (E) Determination of the translation rate in cells from panel D. (F) Determination of the translation rate in PD-L1^high or PD-L1^low CD19⁺CD5⁺ CLL cells from the spleen of C57BL/6 mice after TCL1 adoptive transfer (n = 4). (G-H) Percentage of CLL cells in the blood at the indicated time points (G) and the spleen at euthanasia (H) of C57BL/6 mice after adoptive transfer of splenocytes from a sick Eμ-TCL1 mouse, and treated with vehicle, FL3, anti-PD1 antibody, or the combination FL3/anti-PD1. ∗P < .05, ∗∗P < .01, ∗∗∗P < .001, ∗∗∗∗P < .0001.