Scanning Electron Microscopy of the Interaction between Haemophilus influenzae and organ cultures of rat trachea

Loss of ciliary activity in organ cultures of rat trachea treated with lipo-oligosaccharide from Haemophilus influenzae

“…If LOS acted to reduce mucociliary clearance of organisms by the host it would enhance their ability to colonise and infect the respiratory tract. The sloughing of epithelial cells from the surface of the respiratory tract, which has been observed in vitro (Johnson et al, 1983) might also provide a means by which H . injluenzae can cross the respiratory epithelium to invade the submucosal tissue, with subsequent systemic spread.…”

“…Tracheas were removed aseptically from animals by the method of Johnson et al (1983) and placed in a petri-dish containing Eagle's minimal essential medium (MEM) buffered at pH 7.2 with 50 mM HEPES and supplemented with ampicillin 10 pglml. The MEM was prepared with sterile pyrogen-free water as described by Johnson et al (1983). Each trachea was cut into a series of rings which were placed individually in tissue-culture tubes containing 1 ml of MEM and then incubated at 37°C on a roller drum (Cherry and Taylor-Robinson, 1970).…”

“…Despite the importance of H. injluenzae as a human pathogen, its pathogenicity is incompletely understood. To increase our understanding of this, several experimental systems, including an animal model of meningitis (Moxon et al, 1974) and the use of organ cultures of respiratory mucosa inoculated with H. injluenzae (Denny, 1974;Johnson et al, 1983) have been developed. With the latter system it was shown that ciliary activity in cultures of tracheal rnucosa inoculated with H. injluenzae was lost because of sloughing of epithelial cells (Denny, 1974;Johnson et al, 1983).…”

“…To increase our understanding of this, several experimental systems, including an animal model of meningitis (Moxon et al, 1974) and the use of organ cultures of respiratory mucosa inoculated with H. injluenzae (Denny, 1974;Johnson et al, 1983) have been developed. With the latter system it was shown that ciliary activity in cultures of tracheal rnucosa inoculated with H. injluenzae was lost because of sloughing of epithelial cells (Denny, 1974;Johnson et al, 1983). It was also observed that sterile supernates from infected organ cultures contained a soluble, heat-stable factor that caused loss of ciliary activity when transferred to fresh organ cultures (Denny, 1974).…”

Bacterial toxins which perturb ciliary function and respiratory epithelium

“…aeruginosa elastase caused cytoplasmic blebbing, mitochondrial damage, cell extrusion and loss of cilia in human nasal epithelial cells in vitro (Dowling et al 1997a). Haemophilus influenzae lipopolysaccharide (Johnson et al 1983), Strep. pneumoniae pneumolysin (Steinfort et al 1989) and Bord.…”