Human monocyte-derived macrophage phagocytosis of senescent eosinophils undergoing apoptosis: Mediation by α(v)β3/CD36/thrombospondin recognition mechanism and lack of phlogistic response

Abstract

Eosinophils may mediate tissue injury in a number of allergic diseases. Previously, we reported that eosinophils constitutively undergo apoptosis (programmed cell death) in culture. As this led to phagocytosis of the intact senescent cell by macrophages, we proposed that apoptosis represented an injury-limiting eosinophil disposal mechanism. Ingestion of apoptotic neutrophils by human monocyte-derived macrophages (M∅s) was found to be mediated by adhesive interactions between thrombospondin and the M∅ α(v)β3 vitronectin receptor tritegrin and M∅ CD36. As this failed to elicit a pro-inflammatory response from M∅s, we sought evidence that this specific, nonphlogistic clearance mechanism may op..