CGs from Npc1^−/−.CL4 CTLs are trapped inside enlarged autolysosome-like structures. (A) TEM images of activated Npc1^−/− and Npc1^+/+ CTLs (scale bar, 2 μm) and zoomed-in autolysosome-like structures (scale bar, 200 nm). (B) TEM images of autolysosome-like structures trapping dense-core granules (arrows) from Npc1^−/− CD8⁺ T cells (scale bar, 500 nm). (C) Confocal immunofluorescence microscopy shows colocalization of GzmB (green) and autophagosomal marker LC3-B (magenta) in activated Npc1^−/− and Npc1^+/+ CD8⁺ T cells. Pearson correlation coefficient (bar graph) was used to quantify GzmB and LC3-B colocalization. (D) Total area of LC3-B–labeled structures (as shown in panel C); biological replicates (right). (E) Colocalization of GzmB/LC3-B was assessed using overlap coefficient; biological replicates (right). Detailed description of microscopy and analysis is provided in the data supplement. *P < .05, ***P < .001, ****P < .0001. DAPI, 4′,6-diamidino-2-phenylindole.