Contribution of T cells and NK cells to DC-mediated protection against A20. (A) SCID mice received DC with () or without (×) CpG oligonucleotide as described in “Materials and methods” and were challenged with A20 lymphoma. (B) DCs from CD40-/- mice were used for vaccination of BALB/c mice that were challenged with A20 1 week after the second immunization. indicates without depletion; ▪, NK cell depletion; ▴, CD8⁺ T-cell depletion; and ×, tumor control. The arrow denotes the time point of tumor rechallenge. (C) Long-term memory is independent of CD4+ T cells. BALB/c-derived DCs were used for vaccination of mice that received the CD4+ cell-depleting mAb RmCD4-2 during the priming phase. A20 cells were given 70 days later. indicates without depletion; ▵, CD4⁺ T-cell depletion; and ×, tumor control.