HDIs directly reduce cell-mediated cytotoxicity in an independent system, partly by inhibiting HDAC6.51Cr release assays were used to test the effect of 2 HDIs (NaV and the HDAC6-specific inhibitor tubacin) on cell-mediated cytotoxicity. (A) An NY-ESO–specific CTL cell line (1G4) was cocultured with peptide-loaded target cells after 18-hours pretreatment with HDIs. (B) A CD1d-restricted NKT-cell line was cocultured with α-galactosylceramide–loaded target cells after 18-hours pretreatment with HDIs. ▪ indicate negative control treatment; •, sodium valproate; ▴, tubacin treatment; and ♦, no antigen loaded onto target cells. Treatment with either NaV or tubacin decreased specific lysis at maximal killing by approximately 40% and 20%, respectively. Data plotted are the mean of triplicate measures for one experiment ± 1 SD.
