THE SPECIFIC RECOGNITION BY MACROPHAGES OF CD8( ),CD45RO( ) T-CELLS UNDERGOING APOPTOSIS - A MECHANISM FOR T-CELL CLEARANCE DURING RESOLUTION OF VIRAL-INFECTIONS

Abstract

During viral infections, CD8+,CD45RO+ T populations expand. These primed cells express abundant levels of cytoplasmic granules that contain perforin and TIA-1. Recent work has suggested that the majority of this CD8+ population downregulates Bcl-2 protein expression and is destined to undergo apoptosis. In this study we have investigated the elimination of these apoptotic CD8+ T cells by both human monocyte-derived and murine bone marrow macrophages. We have found that these phagocytes recognize and ingest both apoptotic CD8+ and CD4+ T cells using an alpha v beta 3 (vitronectin receptor)/CD36/thrombospondin recognition system, with the same receptors being used in the recognition of apoptot..