Shew-Meei Sheu1, Jiunn-Jong Wu2,and Bor-Shyang Sheu3 Antrum H. pylori Strains from Mixed-infected Patients expressed higher CagA but Stimulated Diverse IL-8 mRNA Patterns in AGS Cells Shew-Meei Sheu1, Jiunn-Jong Wu2,and Bor-Shyang Sheu3 1Department of Medical Research, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City, Taiwan. 2Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng-Kung University, Tainan, Taiwan. 3Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan Background: Chronic infection with Helicobacter pylori in the human stomach can cause gastritis and peptic ulcers, and is a risk factor for gastric cancer. Mixed infections (co-infection with distinct strains) could facilitate interstrain gene transfer and genetic diversity of H. pylori, allowing its adaptation to the environment of the human stomach. Our previous study found that mixed infections changed the antrum dominant inflammation, which was shown in patients with single infection. The H. pylori virulence CagA (cytotoxin associated antigen) Therefore, it is worth to further investigate, and cytokine secretions of gastric epithelial cells stimulated by the antrum and corpus strains from mixed-infected patients. 2. Aims: To determine whether the antrum and corpus strains from mixed-infected patients express different level of CagA and further induce various cytokines pattern. 3. Materials and Methods: We used the antrum and corpus strains from 3 mixed-infected patients to infect the AGS cells to detect CagA-phosphorylation and IL-8 mRNA levels. 4. Results: The antrum and corpus isolates from 3 mixed–infected patients (a) (b) (c) Figure 1. Random amplified polymorphic DNA (RAPD) banding patterns of isolates from the 3 mixed-infection patients (a, b and c). Cardinal numbers indicate the different isolates from the antrum (A) and corpus (B), and M is HindIII-digested  DNA as a molecular size standard. II. The antrum isolates expressed higher CagA than corpus isolates but the corpus strains induced higher CagA-phosphorylation levels in AGS cells infection Figure 2. CagA expression and its phosphorylation levels of the antrum and the corpus isolates from mixed-infected patients. (a) CagA expression detected from H. pylori lysates; (b) CagA phosphorylation levels determined in infected AGS cells by western blot. Antrum (A) and corpus (B) isolates were from cardinal number 5, 8, and 13 patients. III. The diverse pattern of IL-8 mRNA stimulated by the antrum and corpus isolates from 3 mixed-infected patients Figure 3. The diverse IL-8 mRNA patterns of the antrum and corpus isolates from 3 mixed-infected patients. IL-8 mRNA was detected at 4 and 12 h after H. pylori infected AGS cells. 43504 was as the ATCC reference strain. V. Conclusions: The antrum isolates expressed higher CagA than corpus isolates. However, the higher CagA-phosphorylation levels was induced by the corpus strains, which may be involved in the corpus inflammation and the affected cytokines need to be further demonstrated. 5A3 5B2 A1 2 3 4 5 6 7 8 B1 2 3 4 5 6 7 8 M 9A3 9B5 A2 3 5 6 7 8 B1 3 4 5 6 7 8 M 13A2 13A3 13B2 13B4 13B6 A1 2 3 4 5 6 7 8 B1 2 3 4 5 6 7 8 M