Ammonium Chloride blocks the trafficking of HPV16 to caveosomes. Infection of 293 cells alone in the absence (A and C) or presence (B and D) of 20 mM of lysosome neutralizing agent NH4Cl. Cells were harvested after 5 minutes post binding for early endosome staining with goat anti- EEA1 (A and B), or 2 hours post binding for caveosome staining with goat anti-caveolin 1 (C and D). HPV16 particles were stained using a monoclonal anti-HPV16 L1 antibody H16V.5 (A-D). Images are shown with z-stacks obtained by confocal microscopy. The number of caveosomes (E), HPV16 reporter-virions (E), and colocalization between HPV16 and caveosomes (F) in the absence and presence of NH4Cl were counted using stereology software.