[The vaccinal process after the intramuscular immunization of sheep with Salmonella typhimurium strain 274]. / Vaktsinal'nyi protsess posle vnutrimyshechnoi immunizatsii ovets shtammom Salmonella typhimurium 274.

After the immunization of sheep by the intramuscular injection of S. typhimurium vaccine strain 274 the bacteria did not proliferate, but were phagocytosed and destroyed by leukocytes and macrophages; in some sheep these bacteria persisted up to day 13, inducing inflammation neither at the site of injection, nor in lymphatic nodes and internal organs. The vaccinal process in lymphoid tissue was characterized by an initial decrease in the number of lymphocytes, then a sharp rise in blast transformation, mitosis rate and the number plasmatic cells in the centers of multiplication of follicules in lymph nodes and the spleen. After day 13 gradual normalization began and by day 32 only residual manifestations of immunomorphological changes remained. In the lamina propria of the intestinal mucosa individual small macrophagal granulomas developed. The number of lymphocytes also increased in the epithelium and the lamina propria of the uterine mucosa. In the liver variations in the number of lymphocytes were observed in portal interlayers, around central veins and in the region of sinuses.

[The vaccinal process after the peroral immunization of lambs with the Salmonella typhimurium 274 strain]. / Vaktsinal'nyi protsess posle peroral'noi immunizatsii iagniat shtammom Salmonella typhimurium 274.

After oral immunization of lambs with S. typhimurium vaccine strain 274 these bacteria were characterized by low adhesion to the epithelial surface of the ileum, cecum, and colon, by very insignificant invasion into intestinal epithelium and then into lamina propria of the intestinal mucosa, mesenteric lymph nodes and the blood; the blood stream carried these bacteria further to the liver, spleen and other organs. Bacteria of strain 274 produced no damages, did not multiply and only persisted for 7-13 days in some lambs. No inflammation developed in response to oral immunization of the animals. The developing immunomorphological reaction presented as just a negligible increase in lymphocyte count in the intestinal epithelium, blast transformation and plasmatization in lymphatic follicles of Peyer's patches, hyperplastic mesenteric lymph nodes, blast and lymphocyte recirculation, moderate hyperplasia of white splenic pulp and insignificant lymphoid infiltration of portal interlayers of the liver.

[A morphological evaluation of the harmlessness of noninvasive recombinant Shigella strains]. / Morfologicheskaia otsenka bezvrednosti neinvazivnykh rekombinantnykh shtammov shigell.

The interaction of Shigella recombinant strains (with attenuating chromosomal mutations, with transposon-neutralized plasmid gene mutations, the hybrids of both strains), incapable of inducing keratoconjunctivitis in guinea pigs, with cells Hep-2 and enterocytes in the ligated loop of the small intestine of rabbits was studied. These strains retained, to varying extent, pronounced adhesiveness, but practically lost their invasiveness (though in Peyer's patches the translocation of bacteria by M-cells was observed) and cytotoxicity, as well as their capacity to multiply in epithelial cells and to cause destructive inflammation in the intestine. According to these criteria of evaluation, morphological investigations confirm the safety of the recombinant shigellae under study.

[A morphological evaluation of the protective properties of noninvasive recombinant strains of Shigella]. / Morfologicheskaia otsenka protektivnosti neinvazivnykh rekombinantnykh shtammov shigell.

In 2-3 weeks after the oral immunization of rabbits, made in one or two administrations, with attenuated two-marker S. dysenteriae 1 strain VS-12 and recombinant S. dysenteriae VS-12/S. sonnei NR-18 and S. flexneri y433/S. sonnei NR-18 pronounced immunological reaction developed in the mucous membrane of the small intestine: blast transformation follicles of Peyer's patches, an increase in the number of lymphoblasts and plasmocytes in the cupolae of follicles and in intestinal villi, and an increase in the number of lymphocytes and macrophages in the intestinal epithelium with their release into the lumen of the intestine after challenge with virulent shigellae. The protective potency of these recombinants after challenge with massive doses of virulent shigellae 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 intestinal mucosa.