Donor requirements to transfer antitumor immunity. (A) Donor mice received no treatment, A20 tumor challenge, A20 tumor challenge followed by CTX, or A20 tumor challenge followed by CTX and intratumoral CpG. On day 0 (7 days after the completion of the CpG/CTX vaccine), recipient mice received 9 Gy of TBI followed by 5 × 106 BM cells and splenocytes from donors. One group received a simultaneous boost of 106 A20 cells, which were cultured with CpG-1826 at 3 μg/mL for 72 hours, then irradiated (50 Gy). On day 3 after transplantation, all cohorts of mice received high-dose tumor challenge. (B) On day 15, posttransplantation/transfer mice were bled and assayed by flow cytometry for tumor-specific CD8 T-cell responses as described. Indicated are the percentage of IFN-γ–producing CD8+ live lymphocytes (n = 3 per cohort). (C) Cohorts of mice were followed for bidimensional tumor size, and proportions of tumor-free mice are indicated. One mouse in the “no treatment donor” cohort (first column) showed minimal subcutaneous growth but manifested systemic disease (with hind-limb paralysis) and was killed on day 30.
