This is a single-arm, open-label, single-center, phase I/II study to determine the safety and efficacy of CD19 CAR-T(ssCART-19) combined with autologous T cells engineered to express CD19, namely CD19+ feeding T cells (FTCs), as consolidation therapy in patients diagnosed with de novo Philadelphia chromosome-positive CD19+ B-ALL. The study will contain the following sequential phases: screening, lymphocyte apheresis, induction, and consolidation chemotherapies combined with tyrosine kinase inhibitors. Once in complete response, patients will receive two to four cycles of ssCART-19s, namely one cycle of ssCART-19 infusion (CAR-T1) followed by one to three cycles of ssCART-19 and CD19+ FTC infusion (CAR-T2-4). The role of CD19+ FTCs is to mimic leukemia cells. Therefore, they are expected to stimulate in vivo expansion and persistence of ssCART-19. Considering the limited number of lymphocytes obtained by a single apheresis from patients and cost-efficacy, in addition to safety, we will explore the range of biologically active doses of FTCs in a phase I study. Based on preclinical data, FTCs' stimulation of ssCART-19 at a ratio of 1:1 could achieve the best activation response, so a 5×10\^6/kg dosage of FTCs was set as the initial dosage in the study, and lower doses were also evaluated. In phase I, FTCs will be administered at the dose of 5×10\^6/kg, 3.25×10\^6/kg, or 2×10\^6/kg two hours after ssCART-19 infusion on day 1 and once again administered at the same dose on day 8. After ssCART-19 and FTCs infusion, adverse events (AEs) as the primary endpoints will be recorded for 6 months; efficacy as the secondary endpoint will be assessed by detecting molecular response for 6 months, PFS, and OS for 2 years. In phase II, we will expand the study at optimal biological doses of FTCs and further evaluate the efficacy and safety of the innovative combination therapy of ssCART-19 and FTCs. The primary endpoint was the complete molecular response (CMR). The secondary endpoints were RFS, OS, and adverse events (AEs) of the patients.