Figure 2. Cytotoxic CD4+ CTL clones specific for GV1001 lyse peptide-loaded target cells most efficiently with nested 9-mer epitope. Both HLA-DP and –DQ restricted T-cell clones recognize processed hTERT protein. GV1001-specific T-cell clones were also tested for proliferation against EBV-LCL loaded with recombinant hTERT protein at low concentrations (A). One representative HLA-DP restricted clone is shown (black bars) and one HLA-DQ restricted clone (hatched bars). (B) shows 8- and 24-h ⁵¹Cr-release assays for HLA-DQ restricted CTL clones tested against autologous EBV-LCL loaded with peptides GV1001 (611–626) and nested epitope 618–626. Peptide 617–625 was used as a negative control. Effector: Target ratio was 100:1. Black bars represent clone 18, dotted bars clone 64, and hatched bars clone 76.