[Inhibition of the proteolytic activity of Helicobacter pylori by mouse immune serum]

Area of Science:

• Microbiology and Immunology
• Pathogen-Host Interactions

Background:

• Proteolytic activity (PA) is a key virulence factor in microbial pathogenesis and tissue invasion.
• The specific role of PA in Helicobacter pylori infections and the host's immune response remain incompletely understood.

Purpose of the Study:

• To establish an in vitro system for detecting antibodies that inhibit the PA of Helicobacter pylori.
• To assess the efficacy of mouse serum antibodies generated through different immunization routes against H. pylori PA.

Main Methods:

• Mice were immunized via oral and intraperitoneal routes using a raw bacterial extract (BE) of H. pylori containing PA.
• Serum proteins (SP) from immunized mice were used to assess inhibition of azocasein degradation by H. pylori BE in vitro.

Main Results:

• Serum proteins from orally immunized mice inhibited H. pylori PA by 49.23% at 5 µg/ml, while intraperitoneally immunized mice showed 22.6% inhibition.
• At concentrations above 25 µg/ml, serum proteins from both immunization groups exhibited similar inhibition levels to control serum.

Conclusions:

• A novel methodology was successfully developed for detecting antibodies that inhibit H. pylori PA in immunized mouse serum.
• The findings suggest that oral immunization elicits a more potent inhibitory antibody response against H. pylori PA compared to intraperitoneal immunization.