In contrast, the control and n-butyrate-treated cultures did not reveal any overall difference in FoxP3EGFP-expressing CD4+ T cells (Fig. 2B). Additionally, FoxP3EGFP-expressing CD4+ T cells were not increased in n-butyrate-treated CD4+ T cells re-stimulated in secondary cultures absent n-butyrate (Fig. 2C). Suppressor activity is a functional readout of Treg cell activity. A further evaluation of potential Treg cell activity assessed the capacity of
the n-butyrate-treated CD4+ T cells to suppress proliferation of responder CD4+ T cells in a co-culture suppression assay (Fig. 3). CD4+ T cells (TEFF) from mitogen-stimulated primary cultures were treated with TGF-β or n-butyrate on Day 0. Following 5 days, living TEFF were co-cultured with mitogen-stimulated CFSE-labelled CD4+ T cells (TRESP) for an additional 3 days at titrations
FK506 molecular weight of 2:1, 1:1, 0.5:1 and 0:1 (TEFF:TRESP). The TGF-β-treated TEFF were the only CD4+ T cells from primary cultures that suppressed TRESP proliferation. This suppression was observed at all TEFF:TRESP ratios. In contrast, CD4+ T cells from n-butyrate-treated primary cultures did not suppress TRESP cell proliferation regardless of the TEFF:TRESP ratio. Histone deacetylase inhibitors may prove to be a valuable commodity against unwanted immune responses. This study revealed that n-butyrate anergized mitogen-stimulated CD4+ T cells through blockade of proliferation and IL-2 secretion without enhancement of Treg cell number or function. Defining mechanisms PCI32765 by which HDAC inhibitors block T cell function is important in view of their demonstrated ability to protect the host within autoimmune animal models. For example, the benzamide MS-275 attenuated experimental autoimmune neuritis through reduction of rat sciatic nerve demyelination [22]. T cell and B cell infiltration
as well as EAN-mediating pro-inflammatory Epothilone B (EPO906, Patupilone) cytokines IFN-γ and IL-1β were suppressed. The authors observed an increase in FoxP3 mRNA production in lymph nodes and FoxP3+ sciatic nerve-infiltrating cells 1 day after 6 days of daily MS-275 injections. However, it was not tested further if the beneficial effects of MS-275 were exclusively because of an alteration in Treg cell behaviour. MS-275 similarly was shown to inhibit murine contact hypersensitivity induced by dermal exposure to DFNB (2,4-dinitro-1-fluorobenzene) [23]. MS-275 was topically administered daily for either 4 or 6 days concurrently with DNFB exposure. Within 4 days, lymph node cell numbers decreased threefold in MS-275-treated mice. The authors examined the number of FoxP3+ cells within these lymph nodes and found no significant change in expression on Day 4. However, the lymph nodes revealed a twofold increase in FoxP3+ lymph node cells after 6 days of treatment. These results indicated both that MS-275 offered protection from immune responses and that these protective responses might be mediated independent of Treg cells.