CTSD and infection: Confocal microscopy data demonstrate that intracellular R. montanensis are rapidly destroyed in THP-1-derived macrophages, and several bacterial cells co-localized with the lysosomal markers, LAMP-2 and cathepsin D. In contrast, infection of THP-1-derived macrophages by R. conorii resulted in no significant co-staining with positive structures for both lysosomal markers and the increase of intact bacteria over the time course of the experiment demonstrate their ability to grow.