Detection of nuclear factor kappa B (p65) (upper), inhibition kappa B (middle) and extracellular signal-regulated kinase 2 (bottom) in nuclear and total extracts, respectively at 3, 6 and 12 h after being co-cultured with Helicobacter pylori. Unphosphorylated extracellular signal–regulated kinase 2 (ERK2) was detected as the control in this study[23]. Molecular weights of nuclear factor kappa B (NF-κB), inhibition kappa B (IκB) and ERK2 are 65, 35-37 and 42 kDa, respectively. The assay was carried out with strains at a MOI of 150. AGS: AGS cells co-cultured without H. pylori; HPK5: AGS cells co-cultured with wild-type HPK5; HPKT510: AGS cells co-cultured with cdrA-disrupted mutant HPKT510.