Figure 3.

(A) IR peptide induction of CTL is IL-12 dependent. One day before and one day after immunization with peptide mice were treated i.p. with anti-IL12 antibody (0.5 mg per injection; 4 mg per mouse total dose (Right) or were untreated (Left). For testing the peptide specificity of CTL, ⁵¹Cr-labeled P815 targets were pulsed with peptide at the beginning of the assay (▪) or without peptide (◊). (B) IR peptide induction of CTL is IFN-γ dependent. Wild-type BALB/c mice (Left) or IFN-γ^−/− (Right) were immunized as in A, and tested at 5 weeks. Killing of peptide-pulsed targets (▪) is compared with killing of unpulsed targets (░⃞) at an effector-to-target ratio of 50:1. Similar results were obtained at ratios of 25 and 12.5:1. (A and B) SEM of triplicate cultures were all <5% of the mean.