CTL activity of SC2, SC10, and SC12 soon after infection. Chromium release assays were performed with bulk-cultured PBL of SC2 at 22 DFOSx (A), SC10 at 36 DFOSx (B), and SC12 at 30 DFOSx (C). HLA B8-expressing target cells (B-LCL) were labeled with the indicated HLA B8-binding peptides, and bulk-cultured PBL were used at an effector to target ratio of 60:1 in B, and as indicated in A and C. Spontaneous release was below 20%.