Overall experimental design. Syngeneic A/J donor mice (Donors) were subcutaneously inoculated with 10⁵ live AGN2a cells. The tumor-bearing mice were then either not vaccinated or vaccinated with 2 × 10⁶ irradiated AGN2a-4P vaccine cells subcutaneously at the indicated time points (days). Tumor-bearing recipients (Recipients) were treated with 1100 cGy TBI and 1 day later received intravenous transplantation of 5 × 10⁶ donor bone marrow cells supplemented with unmanipulated T cells, CD25-depleted T cells, or donor T cells containing excess numbers of CD25⁺ cells. Vaccines (irradiated AGN2a-4P cells) were administered to recipients at the indicated time points.