FIG. 5.

B6 mice were inoculated with 10⁶ B.GV tumor cells. At 11 (experiment 1) or 12 (experiment 2) days later, 10⁷ responder spleen cells were mixed with 2 × 10⁵ E♂G2 or LB27.4 (H-2^b/d) tumor stimulator cells, without or with the addition of 2 × 10⁶ viable AKR.H-2^b (experiment 1) or AKR (experiment 2) splenocytes as indicated. At 6 days later, the cells were assayed for the ability to lyse ⁵¹Cr-labeled target cells. The values for spontaneous release by target cells used in either experiment ranged from 4.7 to 15.5%. E:T, effector-to-target-cell ratio.