CagY decorates the <i>H. pylori</i> bacterial surface but is not associated with T4SS pili.

<p><i>H. pylori</i> was co-cultured with AGS gastric cells at an MOI of 100∶1, incubated with antibodies to the CagY MRR or CagA, and imaged by FEG-SEM in the environmental mode. CagY was detected on the bacterial surface of the WT strain but was not associated with pili. CagA was detected both on the bacterial surface and in close approximation to the tips of the pili of the WT strain. There was markedly reduced CagA labeling on the surface of ▵<i>cagY</i> mutant strain compared to the WT strain. No staining was seen when primary antibody was omitted. Pili are sometimes not as well visualized and more often appear broken in these images compared to <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1003189#ppat-1003189-g007" target="_blank">Figure 7</a> due to the lack of metal coating and more frequent washes. Magnification bars indicate 500 nm.