Encyclopedia of Experiments: Immunology
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Transcript
To establish a Helicobacter pylori infection model, begin with an anesthetized, pathogen-free mouse. Restrain the mouse firmly to minimize movement during the procedure.
Take a syringe filled with a bacterial suspension. Connect a polyethylene catheter to the needle of the syringe for intragastric gavage — a technique of delivering the suspension directly into the stomach.
Insert the catheter into the center of the open mouth to access the esophagus, a muscular tube connecting the mouth to the stomach. Gently guide the catheter through the esophagus until it reaches the stomach, and deliver the bacterial suspension directly into its acidic environment.
The inoculated bacteria secrete urease, an enzyme that converts urea into ammonia and carbon dioxide. The ammonia raises the pH of the stomach, neutralizing the acidity and enabling the bacteria to survive.
These bacteria utilize their flagella to traverse through the protective mucus layer, allowing them to reach the gastric epithelium, where they adhere to cells using adhesin proteins. Upon attachment, these bacteria release virulence factors that disrupt the tight junctions between the epithelial cells.
This structural disruption promotes bacterial invasion and colonization in deeper tissues, ultimately establishing a controlled infection in the stomach.
