Redistribution of lysosomes during reovirus infection . HBMECs were either mock-infected or adsorbed with reovirus strain T3D at an MOI of 1 PFU/cell and processed at 18 hpi for confocal and superresolution STED microscopy. Immunofluorescence experiments were conducted using antibodies specific for LAMP-1 (red) and σ1 (mouse monoclonal antibody 9GB5 specific for T3D σ1, green). (A) Confocal micrographs showing lysosomes/SOs (arrows) close to VIs (asterisks). A 3D reconstruction from a series of confocal images is shown on the right. Dashed boxes mark areas in which the LAMP-1 and σ1 signals concentrate in the frontal and lateral projections of the volume. A 3D model is provided in Video 6. (B) Confocal and STED microscopy of a reovirus-infected cell showing association of LAMP-1 and σ1 near VIs (arrow and arrowheads, respectively). High-resolution STED microscopy also showed some sites of colocalization (image on the right). (C and D) Quantification of lysosome distribution in uninfected and infected cells is shown as the mean total fluorescence signal intensity detected at <5 µm or >15 µm from the nuclear rim. Fifty regions of interest were selected using LAS X software (Leica Microsystems). Three representative examples are shown in the left panels. The results are presented as mean fluorescence intensities of LAMP-1 ± SEM (n = 50 regions of interest). **, P < 0.01, unpaired, two-tailed Student’s t test. Scale bars, 10 µm.