D-096. Response of Immune Cells towards Helicobacter pylori Strains of the Kalixanda Study

S. Andres1,2, H-M. Schmidt3, L. Plant1,2, L. Engstrand1,2;
1Swedish Inst. for Infectious Disease Control, Solna, SWEDEN, 2Karolinska Inst., Stockholm, SWEDEN, 3Sch. of Med. Sci., Univ. of South Wales, Sydney, AUSTRALIA.

Background: In a random population-based study, the Kalixanda study, an investigation of the prevalence of peptic ulcer disease in an adult population was carried out. Volunteers of two Swedish communities chosen by using a computerized national population register were evaluated and information was given about the grade of inflammation, gastric diseases and score of Helicobacter pylori organisms present. Out of this study 21 isolates with different host background were selected to study cellular immune response against H. pylori. Methods: The strains were tested for differential cellular immune reactivity. They were exposed to immature dendritic cells (DC’s) derived from peripheral blood mononuclear cells and evaluated for the capacity to impact the maturing process of the immune cells defined by flow cytometry analysis of surface structures and for cytokine production. Additionally the strains were exposed to AGS cells and evaluated for their capacity to induce IL-8 response. The cytokines were detected performing ELISA. Results: The DC’s are obviously influenced by the presence of different H. pylori strains which was shown by the up-regulation of the maturation markers CD80 and CD86. While the differences in maturation are low the DC’s vary in their production of different cytokines. Also the amount of IL-8 produced by AGS cells in response to H. pylori infection varies using different strains. No association could be shown by comparison of the reactions towards bacteria from volunteers with lower and higher grades of inflammation. Conclusion: The 21 strains of the Kalixanda study have different effects on DC maturation and cytokine production as well as AGS cell response measured by IL-8 production. Strains inducing higher and lower response are identified and have to be analysed in depth.