Helicobacter pylori vacuolating cytotoxin binds to the 140-kDa protein in human gastric cancer cell lines, AZ-521 and AGS.

To investigatie a potential mechanism of how Helicobacter pylori establishes infection, we purified a lot of vacuolating toxin (VacA) from supernatant of H. pylori ATCC49503 (tox+ strain 60190). We used an antibody which was prepared by immunizing rabbits with a synthetic peptide consisting of 16 amino acids reflecting a portion (Glu69-Arg83) of amino acid sequence of Vac A. VacA caused vacuoles in human gastric cancer cell lines AZ-521 AGS, and monkey kidney cell line COS-7, but not human promyeloblastic cell line HL-60. By immunoprecipitation analysis using anti VacA antibody, a biotinylated cell surface protein of 140kDa (p140) was precipitated only when the lysates of VacA-susceptible cells were incubated with VacA but not with inactivated VacA, indicating the association of p140 with VacA.