H. pylori and PaCS Figure 4. PaCSs differ from VacA-containing vacuoles and phagosomes. (A, 12,000x, 10 nm gold), (a1, 20,000x), and (a2, 20,000x) H. pylori organisms closely adhering to the luminal surface of colonized cells in superficial gastric epithelium. Note VacA immunoreactivity in bacterial periplasm, cellular early carriers under formation immediately below bacterial adhesion (arrows) and some apical endocytic-endosomal vesicles. (B, 7,000x) Endoluminal bleb of a colonized superficial cell showing immunoreactive VacA in adhering bacteria and some endosomal vesicles fusing each other to form VacA-storing larger vacuoles with inner remnants of original endosomal membranes. (C, 10,000x) Colonized cell showing a large supranuclear phagosome with abundant cytoplasmic remnants and debris and VacA immunoreactivity, enlarged in c (40,000x). (D, 7,000x) HeLa cells incubated for 24 h with H. pylori BCF. Note inside the cell VacA immunoreactivity of some endosomal vesicles, a large vacuole as well as two PaCSs (asterisks) with distinctive particles (d, 60,000x). (E) and (F) (both 55,000x) Small CagA deposits in the subluminal cytoplasm just below two adhering H. pylori. L, gastric lumen; foveolar cell type; e, endosomal vesicle; lc, luminal cleft; n, nucleous; sg, secretory granules; v, vacuole. doi:10.1371/journal.pone.0009716.g004 PLoS ONE | www.plosone.org 6 March 2010 | Volume 5 | Issue 3 | e9716