Western blot of neutrophil-derived COX-2 protein expression. Human neutrophils (1 × 10⁷ cells) were cultured with or without 10 ng/mL of IL-10 or IL-4 in the presence or absence of LPS (100 ng/mL). After 18 hours, cells were procured, cell lysates were centrifuged, and equal amounts of protein (25 μg) were then separated on a 9% SDS-PAGE and subjected to Western blot analysis with 0.25 μg/mL anti–COX-2 MoAb. Similar results were obtained in three separate experiments.