CD4⁺ T cells support in vivo proliferation of CLL cells independently by the antigen specificity. (A) Schematic representation of the experiment. Flow cytometry monitoring of peripheral blood from CD19⁺CD5⁺ cells obtained from a TCL1^+/+ mouse and adoptively transferred into C57 (B), AB0 (C), or OT-II (D) mice. Each line represents a single mouse. Data are a pool of ≥3 independent experiments. (E) Schematic representation of the experiment. CLL appearance was monitored by flow cytometry in the peripheral blood of C57 (F) and Tg7CD45.1 (G) mice. Quantification of CD19⁺ CD5⁺ cells in peritoneal cavity (H), blood (I), spleen (J), and bone marrow (K) of the mice in panels F and G. Each point represents a single mouse. Data are a pool of 2 independent experiments. No statistically significant differences were found using the Student t test.