Deletion of Helicobacter pylori vacuolating cytotoxin gene by introduction of directed mutagenesis

Figure 4 Gastric cancer cells SGC-7901 were co-cultured with the supernatant either from Helicobacter pylori NCTC 11638 or its vacA-knockout mutant strain. 12 h after the incubation, A: cells co-cultured with NCTC 11638 developed vacuoles in the cytosol; B: cells co-cultured with vacA^- mutant strain developed no vacuoles at all.