[32] To address this question, we examined the

modulatory effects of JQ1 cost rHp-CPI on the differentiation of DC from BM precursors. Bone marrow cells were cultured in the presence of GM-CSF to induce DC differentiation and, in one group of cultures, rHp-CPI (50 μg/ml) was added on day 3 of culture. The two groups of BMDC were harvested on day 9 and analysed for cell surface co-stimulatory molecule expression by flow cytometry. Addition of rHp-CPI did not show apparent effects on the yield of BMDC (medium control group, 7·8 ± 1·0 × 106 total cells/plate, 79·1 ± 5·1% CD11c+ DC; rHp-CPI-treated group, 6·9 ± 1·2 × 106 total cells/plate, 74·7 ± 8·2% CD11c+ DC). We observed that, although the control and rHp-CPI-treated DC did not show significant differences in frequencies of CD40+, CD80+ and CD86+ cells in total CD11c+ DC and expression level (mean fluorescence intensity, MFI) of these co-stimulatory molecules, the BMDC that were exposed to rHp-CPI on day 3 of culture

showed reduced expression of the MHC-II molecule by 48% (Fig. 3). The DC that were exposed to rHp-CPI starting on days 5 and 7 of culture also showed reductions in MHC-II molecules by 37% and 14%, respectively, in comparison with the control DC (data not shown). To further analyse the effects of rHp-CPI on DC differentiation, bone marrow cells were cultured for 9 days with or without rHp-CPI, stimulated with the Toll-like receptor (TLR) ligands LPS and CpG and then co-stimulatory molecule expression was examined. Palmatine Both the control DC (cultured in medium alone) and rHp-CPI-treated Obeticholic Acid chemical structure DC showed increased expression of CD40 and CD86 in response to stimulation with LPS in comparison with unstimulated DC. Stimulation of control DC with CpG induced increased expression of CD40 whereas this CD40 expression response was absent in BMDC that were treated with rHp-CPI during the differentiation

stage. Similarly, LPS stimulation increased the CD86 expression in both groups of BMDC, but the rHp-CPI-treated BMDC showed significantly lower levels of CD86 expression following CpG stimulation than the control BMDC. Furthermore, BMDC that were exposed to rHp-CPI during the differentiation stage exhibited significantly decreased expression of the MHC-II molecule in response to stimulation with LPS and CpG compared with the control DC (Fig. 4a,b). The BMDC exposed to rHp-CPI also produced lower levels of IL-6, IL-12p40 and TNF-α cytokines following CpG stimulation compared with the BMDC generated in normal culture conditions (Fig. 4c). These results demonstrate that exposure of BMDC to rHp-CPI during the differentiation stage modified their ability to respond to the activation signal provided by the TLR9 ligand CpG. We next examined the modulatory effects of rHp-CPI on activation of immature BMDC.