Fig. 1

CD68-positive brain myeloid cells after permanent ischemia and simplified scheme of the phagocytic process. Confocal images of the ischemic hemisphere showing cells positive for the lysosomal marker CD68 (red) and for the myeloid cell membrane marker CD11b (green) in the ischemic area at 48 h (a) or 7 days (b) after pMCAo, the latter time showing increased density of CD68-positive cells (nuclei in blue, scale bar = 200 μm). Steps leading to phagocytosis include cell targeting by eat-me-signals, recognition by the phagocytic cell, and vesicular trafficking within the phagocyting cell. There, primary lysosomes get close to cell membrane and fuse with phagosomes. The mature lysosomes complete digestion with lysozimes, leaving residual bodies within the cytoplasm or getting back to Golgi (c). The proximity of lysosomes (labeled by CD68) with cell membrane (labeled by CD11b) can be exploited to measure active phagocytic internalization by confocal microscopy (c′)