EXPERIMENTAL-INFECTION OF HUMAN NASAL MUCOSAL EXPLANTS WITH NEISSERIA-MENINGITIDIS

The interaction of Neisseria meningitidis with rhinopharyngeal epithel ium was studied by experimental infection of explants of human nasal t urbinate 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 chan ged conformation from tall columnar morphology towards cuboidal, and t here was increased discharge of mucus globules from goblet cells. By 2 4 h there was significant damage to infected epithelia, including proj ection of cells out of the surface, cytoplasmic blebbing and mitochond rial abnormalities. Meningococci were associated with surface non-cili ated cells by 4 h after infection. By 24 h after infection they were a ssociated extensively with ah cell types exhibiting damage, There was little association with secreted mucus. In areas of cell damage, penet ration between surface cells was observed. Endocytosis into non-ciliat ed cells was observed in only a minority of explants studied and only in those infected for 24 h. From this intracellular site there was app arent migration to adjacent cells and to intercellular locations. No o rganisms were observed within or beneath basement membrane collagen in any explants but internalisation into mononuclear phagocytes was obse rved occasionally.