[The effects of enzymes and secretions of the gastrointestinal tract on the EB vaccine strain].

Experiments were conducted in vitro. A study was made of the action of the enzymes and of the secretions of the gastrointestinal tract on the viability of the EB vaccine strain. Sensitivity of bacterial cells to the action of saliva, gastric juice, intestinal contents, trypsin, and bile proved to differ. Gastric juice inactivated the vaccine strain which expressed a satisfactory resistance towards the rest of the factors under study practically immediately. There were revealed no significant morphological changes in the cells subjected to the two-hour action of saliva, bile, trypsin and the intestinal content, by means of the electron microscopic examination. These studies permitted to substantiate the rational form of the preparation for oral administration.