Selective detection of phagocytic phase of apoptosis in fixed tissue sections

Degradation of apoptotic cells is finalized during the phagocytic waste-management phase of apoptosis. This eliminates genetic material present in dying cells which often contain pathological, viral, or cancerous DNA. In the waste-management phase, chromatin of apoptotic cells is engulfed and digested by professional phagocytes or surrounding tissue cells. This process is critical for the efficient completion of apoptosis and its detection is necessary in research on cancer and autoimmune diseases where clearance of dying cells plays the central role. Here we present a rapid and simple fluorescence technique for visualization of phagocytic cells participating in waste management. The detailed step-by-step protocol is provided. The approach works in fixed tissue sections and labels all types of active phagocytic cells which engulf and digest apoptotic chromatin.