MORPHOLOGICAL EVALUATION OF THE PROTECTIVE PROPERTIES OF SHIGELLA-NONINVASIVE RECOMBINANT STRAINS

In 2-3 weeks after the oral immunization of rabbits, made in one or tw o administrations, with attenuated two-marker S. dysenteriae 1 strain VS-12 and recombinant S. dysenteriae VS-12/S. sonnei NR-18 and S. flex neri y433/S. sonnei NR-18 pronounced immunological reaction developed in the mucous membrane of the small intestine: blast transformation fo llicles of Peyer's patches, an increase in the number of lymphoblasts and plasmocytes in the cupolas of follicles and in intestinal villi, a nd an increase in the number of lymphocytes and macrophages in the int estinal epithelium with their release into the lumen of the intestine after challenge with virulent shigellae. The protective potency of the se recombinants after challenge with massive doses of virulent shigell ae was found to be high, which was shown by quantitative evaluation of the decrease of adhesion, invasiveness and cytotoxicity, suppression of epithelial lesions and development of inflammation in the intestina l mucosa.