Development of Experimental Platforms to Assess Helicobacter pylori HopQ Interaction with Host CEACAM Molecules.

Background: Helicobacter pylori is an extracellular bacterium responsible for various gastrointestinal diseases, such as peptic ulcers and gastric cancer. It uses multiple mechanisms to colonize the harsh, acidic environment of the stomach and establish its pathogenic processes, mostly through CagA translocation. While cell surface integrin molecules were previously believed to be the main mediators anchoring H. pylori and facilitating this process, recent studies highlight the critical role of the interaction between the bacterial adhesin Helicobacter pylori outer membrane protein Q (HopQ) and host carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) in CagA translocation and subsequent pathogenic signaling. Methods: Recombinant proteins, including HopQ, HopQ-GFP (green fluorescent protein), HopQ-HRP (horseradish peroxidase), and recombinant N-terminal domain of human CEACAM1 (C1ND), were produced via gene cloning, expression, and purification techniques. Ligand-receptor interactions were evaluated using FACS analysis along with antigen- and cell-based ELISA assays. Results: In this study, we have developed antigen and cell-based platforms using recombinant fusion proteins (HopQ-GFP and HopQ-HRP) that effectively interact with recombinant C1ND, as well as various CEACAM molecules expressed on gastric cell lines (MKN45 and AGS). Conclusion: These assay platforms enable detailed investigation of the HopQ-CEACAM interaction and supports high-throughput screening of inhibitors, facilitating the identification of potential drugs or vaccine candidates targeting H. pylori infection.