S100A8 and infection: Since the amount of CagA expressed in AGS cells by the transient transfection experiment was comparable to that of CagA delivered into AGS cells upon in vitro infection with cagA-positive H. pylori (MOI = 100) as determined by the levels of tyrosine-phosphorylated CagA (Fig. S8), such a big difference in CagA-SHP2 complex formation between type I Western CagA and type II Western CagA may also occur in human gastric mucosa infected with Western cagA-positive H. pylori strains.