Aims
The normal intestinal epithelium is increasingly being recognised as an important component of the mucosal innate protection against microorganisms. Human neutrophil defensins 1-3 (HNP 1-3) and lysozyme are components of the systemic innate immunity. The aim of this study was to investigate the expression of HNP 1-3 and lysozyme in normal and active inflammatory bowel disease (IBD) mucosa.
Background/aims
The normal intestinal epithelium is increasingly being recognised as an important component of the mucosal innate protection against microorganisms. Human neutrophil defensins 1-3 (HNP 1-3) and lysozyme are components of the systemic innate immunity. The aim of this study was to investigate the expression of HNP 1-3 and lysozyme in normal and active inflammatory bowel disease (IBD) mucosa.
Conclusion
HNP 1-3 and lysozyme are expressed in surface enterocytes of mucosa with active IBD and they may play an important role in intestinal host defence against luminal microorganisms.
Methods
Mucosal tissue sections were studied by immunohistochemistry using antibodies to neutrophil defensins 1-3 and lysozyme. Extracts of purified intestinal epithelial cells were used for immunoblotting studies and antimicrobial activity against the phoP negative strain of Salmonella typhimurium.
Results
Surface epithelial cells strongly immunoreactive for neutrophil defensins and lysozyme were seen in active ulcerative colitis and Crohn's disease (but not normal or inactive IBD) mucosal samples. Many of these cells coexpressed both of the antimicrobial proteins. Immunoblotting studies confirmed the expression of neutrophil defensins in extracts of purified ulcerative colitis epithelial cells, which also demonstrated antimicrobial activity.