Proinflammatory activation of neutrophils and monocytes byHelicobacter pyloriis not associated withcagA,vacA orpicB genotypes

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Abstract
ChronicHelicobacter pyloriinfection is associated with mucosal inflammation. The aim of the present study was to assess human neutrophil and monocyte activation induced byH pyloristrains with different virulence genotypes. Bacterial sonicates from 12 strains were used to induce phagocyte up‐regulation of adherence molecule CD11b, assessed by fluorescence flow cytometry, and oxidative burst responses, assessed by chemiluminescence. A dose‐dependent induction of the expression of CD11b was observed with sonicate from allH. pyloristrains on both neutrophils and monocytes. Strains negative forcagA andpicB genes had the same inducing activity of upregulation of CD11b as strains positive for these genes. AvacA‐S2 type strain had the same activity asvacA‐S1 type strains. The induction of toxic oxygen radicals byH. pylori‐activatedneutrophils gave higher median values for thecagA‐positive strains than for thecagA‐negative strains. For the monocyte chemiluminescence response,cagA‐negative strains gave higher median values compared tocagA‐positive strains. We conclude that upregulation of the neutrophil and monocyte adherence molecule CDllb induced byH. pylorisonicates is not associated with the presence ofcagA,picB or mosaic pattern ofvacA, and thatcagA,picB‐negative strains andvacA‐S2 strains retain their inflammatory capacity.