Cells were plated in a 24-well plate and stimulated as described above. Cell culture mediumwas collected 6 h after stimulation with milk samples and again after the additional 18 h where cells had been incubated with pure cell culture medium. Samples were diluted 1:1 in 2 TBS containing 0.1% Tween 20. Samples (100 mL) and standards (recombinant human ANGPTL4; 3485-AN, R&D Systems) prepared in TBS containing 5% milk (6 h samples) or 0.1%
BSA (24 h samples) was applied on anti-ANGPTL4 coated ELISA plates (1.6 mg mL1 polyclonal goat IgG in 0.1 M bicarbonate/carbonate buffer, AF3485, R&D Systems) for 2 h at RT. After washing the plate 4 times in PBS containing 0.1% Tween 20, the wells were incubated with a secondary biotinylated antibody to ANGPTL4 (0.8 mg mL1 polyclonal goat IgG; BAF3485; R&D Systems) for 2 h at RT. After another washing step, samples were incubated with
streptavidin-horseradish peroxidase (1:200, DY998, R&D Systems) followed by incubation with TMB solution. The reaction was stopped by adding 0.2 M H2SO4 and absorbance was measured at 450 nm on a microtitre plate spectrophotometer (Synergy 2, Bio- Tek). Each sample was measured three times, and the experiment was performed in duplicate and repeated three times.