Figure 5: Confocal analysis of P. acnes and LAMP1 in THP-1 cells at 24 h p.i. (a) THP-1 cells were infected with P. acnes wild-type strains P6, KPA and 266 at an MOI of 3 for 24 h. Extracellular bacteria were killed with 300 μg/mL gentamycin and removed by washing steps. Cells were fixed, permeabilized, and intracellular bacteria were stained with mouse polyclonal anti-P. acnes antibody and Cy-3 labelled donkey-anti-mouse antibody (red). The lysosomal marker LAMP1 was stained with rabbit-anti-LAMP1 antibody and Alexa Fluor 488 conjugated donkey-anti-rabbit-antibody (green). Actin was stained with Alexa Fluor 647 phalloidin (blue). (b) and (c) Zoom-in on cells infected with P. acnes P6.