OVA-specific IgE titres were defined as the reciprocal of the highest dilution of serum giving a spot of ≥ 5 mm in diameter on the dorsal skin. Total Proteases inhibitor serum IgE concentrations were determined by sandwich enzyme-linked immunosorbent assay (ELISA). Costar plates were coated with 1 µg/ml mouse anti-IgE antibody; 2 µg/ml biotinylated anti-mouse IgE
was used as the detection antibody and purified mouse IgE as the standard (all from BD Biosciences Pharmingen). The limit of detection was 6 ng/ml. In both experimental models, the fatty acid profile was monitored over time in serum samples collected before the start of the intervention and on three occasions during the study feeding period (days 25, 49 and 51 in the DTH model and
days 14, 29 and 39 in the airway hypersensitivity model). Fatty acid (EPA, DHA and arachidonic acid) levels at each time-point were analysed by gas PI3K inhibitor chromatography after conversion to methyl esters [20]. Mouse serum samples (100 µl) were mixed with 2 ml of toluene, 2 ml of acetyl chloride (10%) dissolved in methanol and 50 µl of internal standard (fatty acid 21:0, 0·5 mg/ml) and incubated in a waterbath at 70°C for 2 h. The methyl esters were extracted with petroleum ether; after evaporation, they were dissolved in iso-octane, separated by gas chromatography (Hewlett Packard 5890; Waldbronn, Germany) on an HP Ultra 1 (50 m × 0·32 mm × 0·52 µm DF) column (J&W Scientific, Folsom, CA, USA) and detected by flame ionization. Borwin software 1·21 (Le Fontanil, France) was used to analyse the chromatography data. Mann–Whitney U-test was used to compare groups. Spearman’s rank correlation was used to test for associations. Wilcoxon’s signed-rank test was used to verify within-individual differences in serum fatty acids at the
different time-points. Calculations were performed using spss version 15·0 (SPSS Inc., Chicago, IL, USA). In each of the two runs of this experiment, three groups of 12 mice received control, fish oil or sunflower oil diet. Mice fed fish oil supplemented diet displayed marginally but non-significantly Sunitinib less footpad swelling compared with the other two groups (Fig. 2a). In the sensitization test, lymphocytes from fish oil-fed mice showed significantly reduced OVA-induced proliferation compared with control (P = 0·004) and sunflower oil (P = 0·01)-fed animals (Fig. 2b). Analysis of cytokines in the 2-day supernatants revealed significantly less production of the Th1 cytokine IFN-γ in fish oil-fed mice versus both control mice (P = 0·003) and sunflower oil-fed mice (P = 0·02) (Fig. 2c). Mice fed the sunflower oil diet also showed lower production of IFN-γ compared with control mice (P = 0·01). The overall picture was the same for production of TNF (Fig. 2d) and IL-6 (Fig.