Comparative Study between Helicobacter pylori East-Asian-Type with 39-bp Deletions

Abstract

Introduction: CagA, an oncogenic virulence factor of Helicobacter pylori, may present with 39-bp deletions in the preepiya region of East-Asian strains resulting in a virulent genotype. This study aims to compare the morphological changes, protein expressions, and interleukin-8 (IL-8) production in AGS cells infected with H. pylori East-Asian strains containing 39-bp deletion. Methods: Cultured AGS cells, infected with H. pylori strains obtained from gastric biopsy, were incubated for 24 h (MOI 50, 37°C, 5% CO2). The subsequent changes in cell appearances (Hummingbird phenotype and cell death), protein expressions (CagA, Py99, UreB, and β-actin), and IL-8 production were analyzed through microscopic observation, western blot analysis, and sandwich enzyme-linked immunosorbent assay, respectively. Results: Two H. pylori strains (KPG15 and TN2) and negative H. pylori infection negative control (NC) were observed. Cell death was observable in all three groups. Hummingbird phenotype, inducible by CagA, was present in 39-deletion strains. KPG15 and TN2 exhibited positive bands in UreB, CagA, and Py99-confirming H. pylori presence, CagA expression and phosphorylation, respectively. The higher IL-8 concentrations in KPG15 (820.6 pg/ml) compared to TN2 (742.5 pg/ml) and NC (37.1 pg/ml) may be attributable to CagA-independent IL-8 production. These results support the fact that 39-bp deletion induces more severe inflammation. Conclusions: KPG15 and TN2 displayed similar in silico profiles, cell appearances, and protein expressions. Although both cases induced IL-8 production, KPG15 had a higher result.

Keywords

• caga
• helicobacter pylori
• hummingbird phenotype
• mutation
• sequence deletion