CD19 and leukemia: It was found that the vaccine led to longer in vitro persistence, better expansion of CAR-T cells, synergistic effect on cytolysis of Eps8 + tumor cells, and strong capacity to produce IL-2 (a substantial marker of CAR-T cell potency and persistence) and TNF-α (a vital cytokine for the induction of anti-tumor cellular immunity) upon stimulation with CD19 + leukemia cells [66].