In-vitro hepatotoxic factor in Helicobacter hepaticus, H. pylori and other Helicobacter species.

Several inbred strains of mice in closed breeding colonies were found to have spiral-shaped bacteria associated with active, chronic hepatitis. A new species of Helicobacter, H. hepaticus, was isolated from the infected livers of some strains of mice. Other strains of mice were colonised with H. hepaticus in the caecum and colon, but not the liver. Filtersterilised supernatant fluid from five strains of H. hepaticus was tested in a mouse liver cell line (ATCC no. CCL 9.1) for cytotoxic activity. All strains produced a toxic factor causing morphological changes in the cells at dilutions up to 1 in 1000. Toxicity was observed after exposure to the supernatant fluid for 48-72 h. Other Helicobacter spp. that also produced the cytopathic effect (CPE) in the liver cell line were H. felis, H. acinonyx, H. pylori and one strain of H. mustelae. "Helicobacter rappini" and H. muridarum did not cause CPE in the liver cells. The soluble factor was stable at 4 degrees C for up to 3 months. It was also stable at 56 degrees C for 30 min, but was inactivated by boiling for 15 min. It was inactivated by incubation with trypsin. A partially purified preparation of the cytotoxin had a mol. wt of c. 100,000 and did not have urease activity. The cytotoxin produced by H. hepaticus did not cause vacuole formation in HeLa cells.