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Lactoperoxidase and human airway host defense
Corinne Wijkstrom-Frei1, Souheil El-Chemaly, Radia Ali-Rachedi
1Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Miami School of Medicine, Miami, FL 33101, USA.
American Journal of Respiratory Cell and Molecular Biology
|March 11, 2003
Summary
The lactoperoxidase (LPO) antibiotic system is present in human airways, contributing to host defense. This system shows antibacterial activity against common airway pathogens like Pseudomonas aeruginosa.
Area of Science:
- Immunology
- Microbiology
- Respiratory Medicine
Background:
- The lactoperoxidase (LPO) system is a known component of mammary and salivary secretions.
- Previous studies indicated LPO's function in ovine airways.
Purpose of the Study:
- To investigate the presence and function of the LPO system in human airways.
- To assess LPO's role in host defense against respiratory pathogens.
Main Methods:
- Analysis of human airway secretions for LPO enzyme activity and thiocyanate (SCN-) presence.
- Western blot and RT-PCR to detect LPO protein and mRNA.
- Immunocytochemistry to localize LPO.
- Testing antibacterial activity of secretions against specific pathogens.
Main Results:
- Human airway secretions contain significant LPO enzyme activity and sufficient SCN- concentrations.
- LPO mRNA and protein were detected in human tracheal tissue and secretions.
- LPO was localized to submucosal glands in bronchi.
- Airway secretions demonstrated LPO-dependent antibacterial activity against Pseudomonas aeruginosa, Burkholderia cepacia, and Haemophilus influenzae.
Conclusions:
- A functional lactoperoxidase (LPO) antibiotic system is present in human airways.
- This system likely contributes to the innate immune defense of the airways against bacterial infections.