(A) BMDCs were treated with or without C2 (1 mM), C4 (0.5 mM), or TSA (10 nM) for 24 hours, and HDAC activity was measured by the HDAC activity assay kit, and determined by using fluorescence intensity at excitation/emission (490/525 nm). (B) Splenic B cells were cultured with BMDCs in the presence of C2 (1 mM), C4 (0.5 mM), or TSA (10 nM) for 5 days, and IgG production in supernatants determined by ELISA. (C) BMDCs were pretreated with or without C2 (1 mM), C4 (0.5 mM), or TSA (10 nM) for 6 hours, and cultured with B cells for 5 days. IgG levels were determined by ELISA. One representative of three independent experiments was shown. The data were expressed as mean ± s.e.m. *p < 0.05, **p < 0.01.