B Confocal immunofluorescence microscopy images of P1.HTR cells transfected with IDO1.WT, co-stained with antibodies recognizing IDO1 (green) and markers of intracellular organelles and structures (as indicated; red). Nuclei were stained with DAPI (blue). The merge imagine is shown for all stainings or without DAPI (no DAPI). Scale bar, 10 µm. 