to migrate and present antigen to T lymphocytes in the dLN. + 11 Skin-derived CD11c DC from Compound A-treated mice are less effective at stimulating naive T lymphocytes In an effort to understand how antagonism of CRTH2 can modulate DC-mediated T cell activation, we examined activated skin-derived CD11c+ DC for their ability to stimulate naive T cells. BALB/c mice were painted on a shaved section of dorsal skin with FITC, as well as receiving either Compound A or vehicle concomitantly. Eighteen hours later, the dLNs were isolated, and both FITChi+ and FITC CD11c+ DC were isolated by Facsorting. Notably, the Compound A-treated mice had lower percentage of FITChi+ DC comprising the total CD11c+ population than vehicle-treated mice. This suggests a decreased migration of CD11c+ skin-derived DC to the dLNs at 18 h post-FITC painting. The various populations of DC were co-cultured with a 10fold excess of naive CD4+ T lymphocytes isolated from DO11.10 TCR transgenic mice and the OVA323339 peptide. As a control, splenic CD11c+ DC were isolated from the two groups of FITC-painted mice and co-cultured with T cells and antigen. After 72 h, the culture supernatants were harvested and assayed for various cytokines. As shown in Fig. 8, FITChi+ DC from Compound A-treated mice were generally much less effective at eliciting cytokine production from naive T cells than FITChi+ DC from vehicle-treated mice. In particular, production of IL-17A, IFN-c, IL-10 and IL-6 were substantially decreased in cultures containing FITChi+ DC from Compound A-treated mice. For instance, IL-17A purchase SB 203580 levels were reduced to;50%, and there was a 40% decrease in the amount of IFN-c produced, and this decrease was readily detectable after 48 h in culture. Levels of IL-4, although low in all conditions tested, were not significantly altered among the different DC populations. Similarly, the levels of transforming growth factor -b1 and IL-27, a negative regulator of Th17 differentiation, were not impacted between the different DC populations. An examination of cytokines that could be produced by the DC directly revealed that no IL-12, IL-6 or IL-10 was detected in the supernatants from any of the DC populations cultured in the absence of T cells and antigen. The possibility does remain, however, that DC could have been induced to produce the IL-6 and IL-10 upon culture with the naive T cells and antigen, as opposed to this being exclusively T cell-mediated cytokine production. Using qPCR, no significant differences in the RNA levels of IL-23/p19 were Fig. 6. CRTH2 antagonism results in reduced serum levels of OVA-specific antibodies in epicutaneously ovalbumin-sensitized BALB/c mice. Mice were sensitized epicutaneously on days 17, with either PBS or OVA, and dosed daily with either drug vehicle or compound A for the same time period. Serum was isolated on days 4, 9, 14 and 21 and assayed for OVA-specific IgE, IgG1 and IgG2a. Closed squares–PBS/ vehicle cohort, closed circles–OVA/vehicle cohort and open PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19825521 circles–OVA/Compound A cohort. Each point shown is the mean 6 SEM. Mice were i.p. immunized with 10 lg OVA dissolved in alum or alum alone on day 1. On day 21, the mice receiving the OVA/ alum were epicutaneously sensitized with OVA for 7 days, and one cohort received Compound A for days 2127. Serum was isolated on days 4, 9, 21, 28 and 35 and OVA-specific IgE antibodies were measured. The three groups were as follows: closed squares–alum alone and PBS epicutaneously immunized, cl