Dll4^hiDC-induced T cells retain potent antileukemia activity. Dll4^hiDCs were generated from BM of BALB/c mice. Then, the Dll4^hiDCs were cultured with allogeneic B6 CD4⁺ T cells for 5 days (DCs/T cells = 1:4). Lethally irradiated (8 Gy) BALB/c mice were injected with B6 TCD-BM (5.0 × 10⁶) mixed with in vitro activated allogeneic CD4⁺ T cells. In addition, A20^TGL leukemia/lymphoma cells (1.0 × 10⁶) were injected to these recipients 2 hours before transplantation to induce leukemia. (A, B) The numbers of Dll4^hiDC-induced CD4⁺ T cells were titrated from 0.5 million (M) to 2.5 M. B6 TCD-BM with or without addition of unstimulated B6 CD4⁺ T_Ns were transferred to lethally irradiated BALB/c mice as controls. (A) Survival of the recipients was monitored over time. (B) Pictures show in vivo detection of luciferase activity at days 14, 28, and 77 after transplantation. Data shown here are pooled from 2 independent experiments. (C) Histograms show the expression of tested markers on the surface of Dll4^hiDC-induced CD4⁺ T cells. (D-F) Dll4^hiDC-induced CD4⁺ T cells were flow sorted into CD4⁺CD44^hiCD62L^lo cells (0.5 × 10⁶) and CD4⁺CD44^loCD62L^hi cells (0.5 × 10⁶) and transferred together with TCD-BM into lethally irradiated leukemia BALB/c mice. (D) Survival of the recipients was monitored over time. (E) Histogram shows GVHD clinical scores at days 10 and 20. (F) In vivo images of the luciferase-positive leukemia cells at days 14, 28, and 70 were shown. Photographs were taken by Xenogen IVIS 100. Data shown here are pooled from 2 independent experiments. *P < .05; **P < .01; ***P < .001.