[Shigella interaction with immune enterocytes].

The immunity induced in rabbits by oral immunization with Boivin Shigella polyantigen results in activation of enterocytes: hypertrophy and dilatation of the Golgi apparatus and endoplasmic reticulum, increase in the number of sizes of primary and secondary lysosomes. Resistance of the immune enterocytes to Shigella is manifested in a decreased number of bacteria able to penetrate the cytoplasm, the absence of lysis of heterophagosome membrane surrounding the organisms, and the lack of fusion of the heterophagosomes with primary and secondary lysosomes. The bacteria are even destroyed in the immune enterocyte phagolysosomes. At the same time after the challenge of the rabbit gut loops with 10(9) Shigella some bacteria overcome the immunity, lyse the heterophagosome membranes and multiply directly in the enterocyte cytoplasm, as occurs in nonimmune control rabbits. As a result, ulcerative inflammation develops as in the controls, sometimes even accompanied by hypersensitivity reaction. Fluid accumulation in rabbit gut loops challenged seems to be associated with the effect of Shigella enterotoxin(s), both cytotoxic and cytotonic, as suggested by the peculiar manifestations of enterocyte hypersecretion and damage.