Figure 6.

CTL‐mediated antitumour activity. (A) CTL‐mediated cytotoxicity in vitro. The cytotoxic activity of spleen lymphocytes was measured in 4‐hr ⁵¹Cr‐release assay. The enriched T lymphocytes were added to ⁵¹Cr‐labeled CT26 cells immediately after isolation from spleens. T cells derived from the spleens of p‐c (□) treated mice showed higher cytotoxicity against CT26 cells than those from e‐p treated (▪), liposome alone (▴) and PBS (◯) groups (P < 0.05). (B) Abrogation of CTL‐mediated cytotoxicity in vitro. CTL‐mediated cytotoxicity is abrogated by certain kinds of mAbs as described in Materials and Methods. The ratio of effector:target cells was at 40:1. The p‐c induced tumour cytotoxic activity can be blocked by anti‐CD8⁺ or anti‐MHC I (anti‐H‐2K^b/H‐2D^b) mAb. Similar results can be found at other ratios.