Irradiated SDF-tumor cells support the induction of systemic prophylactic and therapeutic immunity.
(A) C57BL/6 mice (10 mice/group) were vaccinated intravenously with irradiated 2 × 105 control C1498 (●) or SDF-C1498 (○) cells and challenged a week later with live 2 × 105 wild-type C1498 cells. Vaccination with SDF-C1498 cells resulted in 90% protection and resistance to wild-type tumor challenge; all the mice in the control group developed lethal leukemia. The graph is representative of 2 independent experiments. (B) C57BL/6 mice (10 mice/group) were vaccinated intradermally in one flank with irradiated 105 control B16F1 (●) or SDF-B16F1 (○) cells and challenged a week later in the opposite flank with live 105 wild-type B16F1 cells. Vaccination with SDF-B16F1 cells resulted in 70% protection of the mice and resistance to wild-type tumor challenge; vaccination with wild-type B16F1 only protected 10% of the mice. The graph is representative of 2 independent experiments. (C) C57BL/6 mice (10 mice/group) were injected intravenously on day 0 with live 2 × 105 wild-type C1498 cells. On day 3, they were vaccinated intravenously with irradiated 105 control (▪) or SDF-C1498 (●) cells. A third group of mice was vaccinated twice (day 3 and 8 after live wild-type tumor inoculation) with 105 SDF-C1498 cells (○). One vaccine on day 3 resulted in 40% leukemia-free survival; vaccines on day 3 and 8 resulted in 30% leukemia-free survival. These results were replicated in a second experiment. (D) C57BL/6 mice (10 mice/group) were injected intradermally on day 0 with live 105 wild-type B16F1 cells and vaccinated on day 3 with irradiated 105 control (▪) or SDF-B16F1 (●) cells. Vaccination with SDF-B16F1 cells resulted in 40% cure of tumors and long-term tumor-free survival. The graph is representative of 2 independent experiments.
