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Experimental infection of human nasal mucosal explants with Neisseria meningitidis
1Department of Microbial Diseases, City Hospital, University of Nottingham.
Abstract:
The interaction of Neisseria meningitidis with rhinopharyngeal epithelium was studied by experimental infection of explants of human nasal turbinate mucosa with two wild strains: a fully capsulate case isolate, and an epidemiologically related non-capsulate nasopharyngeal isolate. After incubation for 4 h, epithelial cells of infected explants changed conformation from tall columnar morphology towards cuboidal, and there was increased discharge of mucus globules from goblet cells. By 24 h there was significant damage to infected epithelia, including projection of cells out of the surface, cytoplasmic blebbing and mitochondrial abnormalities. Meningococci were associated with surface non-ciliated cells by 4 h after infection. By 24 h after infection they were associated extensively with all cell types exhibiting damage. There was little association with secreted mucus. In areas of cell damage, penetration between surface cells was observed. Endocytosis into non-ciliated cells was observed in only a minority of explants studied and only in those infected for 24 h. From this intracellular site there was apparent migration to adjacent cells and to intercellular locations. No organisms were observed within or beneath basement membrane collagen in any explants but internalisation into mononuclear phagocytes was observed occasionally.
Insights
Neisseria meningitidis invades the nasal lining, causing epithelial cell damage and mucus release. The bacteria penetrate between cells and are occasionally internalized by immune cells.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Neisseria meningitidis is a significant human pathogen.
- Understanding its initial interaction with the respiratory epithelium is crucial for disease prevention.
Purpose of the Study:
- To investigate the interaction between Neisseria meningitidis and human rhinopharyngeal epithelial cells.
- To characterize the early cellular changes and bacterial invasion mechanisms.
Main Methods:
- Experimental infection of human nasal turbinate mucosa explants with Neisseria meningitidis.
- Microscopic analysis of epithelial cell morphology, damage, and bacterial association over time.
Main Results:
- Neisseria meningitidis induced rapid epithelial cell shape changes and increased mucus secretion.
- Significant epithelial damage, including cell blebbing and mitochondrial abnormalities, was observed within 24 hours.
- Bacteria associated with damaged cells, penetrated intercellularly, and were occasionally internalized by non-ciliated cells and phagocytes.
Conclusions:
- Neisseria meningitidis causes direct damage to the respiratory epithelium.
- Intercellular invasion and limited intracellular uptake contribute to the host-pathogen interaction.