The use of a 49.6 kDa pili protein of Helicobacter pylori for serological diagnosis in mice

Bacterial culture is currently not recommended for routine evaluation of H. pylori infection in humans. For this reason, serological techniques play a critical role in diagnosing H. pylori infection in humans, particularly for initial pre-endoscopy or pre-treatment screening in dyspeptic patients. However, several current “in-office” tests appear to be less accurate or would need further validation before being recommended for use in a primary clinical care level. Preparation of specific and immunogenic antigens is an important step to improve the sensitivity and specificity of serologic assays, particularly for confirming the peptic ulcer status. The purpose of this study was to use a sub-unit protein of H. pylori with a molecular mass of about 49.6 kDa for the evaluation of H. pylori infection in mice. Fifty mice were orally infected with live H. pylori, and a similar number of mice were only orally given sterile phosphate-buffered saline (PBS). This process was repeated three times with a three-day interval between each administration, and blood samples were collected before and after each infection. The sera were tested using dot blot and ELISA. Seroconversion was detected two weeks after infection, and ELISA showed 98% for both its sensitivity and specificity. This study has indicated that the 49.6 kDa subunit pili proteins recognized homologous antibodies against the microorganism. Further studies are required to confirm the reaction of this protein against serum originated from H. pylori-infected human.