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Opsonic requirements of Helicobacter pylori
A W McKinlay1, A Young, R I Russell
1Gastrointestinal Unit, Glasgow Royal Infirmary.
Abstract:
The opsonic requirements of Helicobacter pylori were investigated in a series of experiments with human polymorphonuclear leucocytes (PMNL). Pre-incubation of H. pylori with pooled normal human serum (NHS) in concentrations of 5-20% significantly increased the uptake of radiolabelled bacteria by PMNL. Treatment of the bacteria with NHS 30% caused the release of radiolabel and this effect was abolished by heating serum to 56 degrees C, suggesting that H. pylori is serum-sensitive and that complement is involved. Opsonisation of H. pylori with NHS concentrations of 10-30% significantly increased PMNL chemiluminescence. Removal of specific antibody had no effect. Removal of either the classical or alternative complement pathways produced no significant change in PMNL chemiluminescence, indicating that either pathway is sufficient for opsonisation on its own. The results confirm that complement is the most efficient opsonin for H. pylori.
Insights
Complement, specifically human serum, acts as the most effective opsonin for Helicobacter pylori, enhancing its uptake by human polymorphonuclear leucocytes (PMNL). This indicates H. pylori is serum-sensitive and complement-mediated opsonization is crucial for its interaction with immune cells.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Helicobacter pylori is a significant human pathogen.
- Understanding its interaction with the host immune system is crucial for developing effective treatments.
- Opsonic requirements dictate the efficiency of phagocytosis by immune cells.
Purpose of the Study:
- To investigate the opsonic requirements of Helicobacter pylori.
- To determine the role of human serum and complement in H. pylori opsonization.
- To assess the impact of opsonization on phagocyte function.
Main Methods:
- Experiments using human polymorphonuclear leucocytes (PMNL).
- Incubation of H. pylori with varying concentrations of normal human serum (NHS).
- Measurement of bacterial uptake and PMNL chemiluminescence.
- Serum heat inactivation and complement pathway manipulation.
Main Results:
- NHS significantly increased H. pylori uptake by PMNL.
- H. pylori demonstrated serum sensitivity, with complement involvement confirmed by heat inactivation.
- NHS opsonization significantly enhanced PMNL chemiluminescence.
- Neither specific antibody nor individual complement pathways (classical/alternative) were essential for opsonization.
Conclusions:
- Complement is the most efficient opsonin for H. pylori.
- Both classical and alternative complement pathways can mediate H. pylori opsonization.
- H. pylori is sensitive to complement-mediated lysis and opsonophagocytosis.