To estimate the adhesion ability of bacteria to gastric
epithelial cells by flow cytometry, the bacteria were
labeled with the PKH2 Green Fluorescent Cell Linker Kit
(SigmaeAldrich) following the manufacturer’s instructions.
Briefly, bacteria were suspended in F12 medium and
adjusted to OD600 Z 1.0. A 500-mL sample of the bacterial
suspension was centrifuged and suspended in 1 mL diluent A
containing 1.5 mL PKH2 dye. After 4 minutes’ incubation,
the labeling reaction was stopped by adding 1 mL FCS. The
labeled bacteria were washed with F12 medium with 2% FCS
and 0.1% bovine serum albumin, and finally suspended in
0.1% bovine serum albumin.