HDAC-i inhibits proliferation of T cells.

PBL cultures (A-D,F) or purified CD4 T cells (E) were treated without or with the indicated amount of FR901228 (A-E) or trichostatin A (F) for 2 hours prior to stimulation with 3 × 28 beads (A,E,F), ionomycin/PMA (B), or allogeneic dendritic cells (C). Proliferation was measured by MTT assay after 3 (A-B) or 6 (C) days of stimulation (stim). Panel D shows a flow-cytometric profile of CFSE-labeled PBL cultures 6 days after stimulation with 3 × 28 beads in the presence or absence of 20 ng/mL FR901228, added before or after stimulation as indicated.