Immunotransplantation enhances tumor-specific T-cell responses and protects against high-dose tumor challenge. (A) Mice received either no vaccine, vaccination with CpG/CTX, or syngeneic BM and CFSE-labeled splenocytes from vaccinated donors after either no irradiation (“full” recipients) or 900 cGy of TBI (“empty” recipients). On day 3 after transplantation, mice (10 per cohort) were challenged with 10⁷ A20 cells subcutaneously. (B,D) On day 15 after transplantation, mice were bled and PBMCs tested for tumor-specific IFN-γ production. (B) Graphs are gated for CD3⁺ lymphocytes, and statistics are IFN-γ⁺ cells as a percentage of all CD44^hi cells. (C) Tumor growth curves are composites for each cohort. Error bars represent plus or minus 1 SD. (D) (Top right panel) Mean fluorescent intensity (MFI) of IFN-γ–producing cells related to CFSE dilution. The MFI of IFN-γ⁺ cells (5.1) is lower than that of IFN-γ⁻, 12.1. (Bottom panels) “Empty” mice contain more (22.5%) CD3⁺CD44^hi cells (defined as in panel A) than their “full” mice counterparts (1.7%). (E) On day 45 after transplantation, 9 mice were rebled and PBMCs were separately assayed as in panels B and D, except that gated are CD8⁺ cells and indicated are the proportion of IFN-γ⁺ cells as a percentage of CD44^hi cells.