Fig. 3.

Cytotoxicity induced by CD8⁺ T and NK cells. Splenocytes were isolated from BALB/c mice after vaccination with experimental or control DNA vaccines 2 wk after challenge with D2F2 tumor cells and analyzed for their cytotoxic activity in a ⁵¹Cr-release assay at different effector-to-target cell ratios. (Upper) Specific lysis mediated by CD8⁺ T cells against D2F2 target cells (▴), which was blocked by an anti-MHC-class I Ab (H-2K^d/H-2D^d)(▪). (Lower) Lysis mediated by NK cells (•) against Yac-1 target cells. Each value shown represents the mean of eight animals.