Fig. 6.

RA treatment sensitizes UM cells to MHC class I-restricted peptide-specific lysis. a The HLA A11+ UM cell line OCM-1, either untreated (open diamonds) or treated with RA for 6 days (closed squares) was pre-pulsed with 0.1 μg/ml of the IVT peptide and tested for sensitivity to lysis by the peptide specific HLA-A11-restricted CD8⁺ CTL clone BK289 in a standard 4 h ⁵¹Cr-release assay at the indicated effector-to-target ratio. Cells non-pulsed with peptide (triangle for untreated and black cross for RA treated) were used as controls. b OCM-1 cell line either untreated or treated with RA was pre-pulsed with the indicated concentrations of IVT peptide and tested in a 4 h ⁵¹Cr-release assay against the CD8+ CTL clone BK289 at a 5:1 effector-to-target ratio. One representative of three performed experiments is shown. c Percent increase in cytotoxicity at the indicated E:T ratio achieved after RA treatment is expressed as the mean ± SD of three independent experiments. d Percent increase in cytotoxicity at the indicated peptide concentrations achieved after RA treatment is expressed as the mean ± SD of three independent experiments. CTL clones CAR30 and BK210 were also used as effectors in experiments shown in panels “c” and “d”