The protein samples were reduced, alkylated, and then digested with trypsin using standard protocols

total protein. There were a minimum of five mice per treatment group. P < 0.001, P < 0.01. Interestingly, there was a 3- to 4-fold induction of TSLP in ears challenged with just acetone:dibutyl phthalate compared with a naive ear. There was also no significant difference in the TSLP levels from control ears of mice treated with drug Veh or Cmpd A, demonstrating that the CRTH2 antagonist effect on TSLP production was limited to allergen challenge. Finally, there was no detectable IL-1b or TSLP 1 h post-FITC challenge. Anti-TSLP can modulate FITC-induced ear swelling and cytokine production We next used an anti-TSLP-neutralizing mAb to investigate the role of TSLP in this acute allergic dermatitis model in greater depth. Mice were first sensitized to FITC and 6 days later were treated with Cmpd A, a suboptimal dose of Cmpd A plus an isotype-matched antibody, an anti-TSLP antibody and anti-TSLP antibody together with 0.1 mg kg1 Cmpd A. Twenty-four hours after FITC challenge, ear swelling was assessed, and the ears were then harvested for histological analysis and cytokine production. In this experiment, 1 mg kg1 of Cmpd A reduced ear swelling;70%, and the 0.1 mg kg1 dose was expectedly less efficacious . A similar reduction in ear swelling was seen in the antiTSLP-treated mice. However, the co-administration of 0.1 mg kg1 Cmpd A and anti-TSLP reduced the inflammation to levels observed with the 1 mg kg1 Cmpd A treatment. This synergistic effect between Cmpd A and anti-TSLP suggested that multiple pathways lead to allergic inflammation and skin lesions and that TSLP played only a partial role. In contrast, the amelioration of ear swelling and reduction of TSLP by Cmpd A suggests that the CRTH2 antagonist can inhibit multiple pathways leading to allergic inflammation in this acute model of contact dermatitis. H and E analysis of ear sections shows a large inflammatory infiltrate and pustule formation from animals treated with drug Veh, 0.1 mg kg1 Cmpd A and anti-TSLP. Animals receiving 1 mg PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19826300 kg1 Cmpd A and both anti-TSLP together with 0.1 mg kg1 Cmpd A had a decreased inflammatory infiltrate. An examination of IL-4 levels showed an;40% decrease upon 1 mg kg1 Cmpd A treatment. Similar to the ear swelling, both suboptimal levels of Cmpd A or anti-TSLP treatment reduced IL-4 to an intermediate level, and the combination of both resulted in a decrease comparable to the 1 mg kg1 dose of Cmpd A. This suggests that IL-4 is being induced by both TSLP-dependent and independent pathways. Interestingly, FITC-induced skin inflammation is CRTH2 dependent 89 Fig. 4. Cmpd A reduces MIP-2 and GRO-a production and the recruitment of neutrophils in FITC-challenged ears. AEB 071 web protein lysates from challenged ears isolated at 8 and 24 h were assayed by ELISA for MIP-2 and GRO-a protein levels. Values shown are the petagram of cytokine measured from 50 lg total protein, and the average of five mice per treatment group 6 SEM is shown, as detailed in the Materials and methods. The treatment groups are Veh/veh, FITC/veh, FITC/Cmpd A 10 mg kg1 p.o. and FITC/Dex 5 mg kg1 intra-peritoneally IHC analysis of ears isolated at 24 h post-FITC challenge and stained with an anti-GR-1 mAb to label neutrophils. Fig. 5. IL-1b and TSLP protein levels are reduced 4 h after FITC challenge by Cmpd A. Mice were treated with either drug Veh or Cmpd A 1 h before FITC challenge to the right ear. The left ears were challenged with FITC Veh. After 4 h, the ears were harvested and the protein l