Critical role of CD4+ T cells in the priming phase of the Id-specific immune response. Mice were depleted with 300 μL anti-CD4 (▪), anti-CD8 (▾), or anti-CD4 + anti-CD8 mAbs (⬡) at days -3, -1, +2, and +5 relative to vaccination (day 0) with 0.3 × 10⁶ DCs infected with rVV-Id-LAMP1 (A), rVV-Id (B), or rVV-S65L (^*). indicates nondepleted mice. At day 14, mice were challenged with 1000 38C13 viable tumor cells subcutaneously and followed for survival.