S100A8 and infection: The stronger apoptotic action exerted by the CagA-defective strain in comparison to its parental strain appeared completely due to its VacA production since, when infection of MKN 28 cells with H. pylori was carried out in the presence of an excess of the dominant-negative purified VacA Δ6-27 mutant cytotoxin [8],[38], we found an apoptosis level virtually identical for all the three strains tested (i.e., the wild-type and its isogenic mutants lacking CagA or VacA, respectively) (Figure 6).