[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.

[Protection from virulent Salmonella groups B and D after the peroral immunization of chicks with a hybrid of Salmonella typhimurium and Salmonella dublin]. / Zashchita ot virulentnykh sal'monell grupp B i D posle peroral'noi immunizatsii tsypliat gibridom Salmonella typhimurium i Salmonella dublin.

Chickens over 10 days old, infected orally with virulent salmonellae, were found to remain alive. Histologic investigation showed the development of mild enteritis and more pronounced, lasting for more than two weeks, inflammation of the cecum, dissemination and focal lesions in the liver (granulomas, necrosis). In experiments on the oral immunization of 3-day old chickens the bivalent hybrid of S. typhimurium vaccine strain 274 and S. dublin induced only pronounced blast transformation in lymphatic follicles of the cecum, hyperplasia of activated macrophages and formation of granulomas from these macrophages and lymphocytes. After oral challenge of the immunized chickens with virulent salmonellae of group B (S. typhimurium) and group D (S. enteritidis, S. gallinarum-pullorum) the chickens exhibited sharply pronounced protection against adhesion, colonization and invasion, and a few penetrating bacteria were rapidly destroyed by immune macrophages. Hybrid strain 274/O9 proved to be suitable for use as oral bivalent vaccine against salmonellosis in chickens.

[The host reaction to the administration of different components of Coxiella burnetii]. / Reaktsiia khoziaina na vvedenie razlichnykh komponentov Coxiella burnetii.

After the intraperitoneal injection of corpuscles of C. burnetii antigen (Ag), phospholipid (PL), and sediment obtained after the extraction of PL from Ag with chloroform-methanol (CM) slight leukocytic reaction developed in the peritoneum on day 1, and on day 2 it could be observed in the liver and in the spleen. Ag induced the most pronounced morphological changes. In the spleen they were manifested by the activation of T- and B-dependent zones of white pulp from day 2 and by the pronounced hyperplasia of reticular cells and macrophages, leading to splenomegaly, by days 7-14. Simultaneously lymphoid-macrophagal granulomas and hepatomegaly developed in the liver. By days 7-14 the foci of necrosis in the liver were caused by the thrombosis of portal veins and were not registered after the injection of PL and CM (and earlier also in experiments with Ag in doses of 0.1-0.3 mg).

[Current views on the pathomorphology and pathogenesis of dysentery]. / Sovremennye vzgliady na patomorfologiiu i patogenez dizenterii.

According to the literature and the authors' data in patients who died of dysentery Shigellae are found seldom because of postmortem shedding of superficial colonic epithelium infected by them. Shigella adhesion and invasion into the colonocytes are regularly found in the colon biopsies. As shown recently in experiments, Shigella outer membrane proteins forming "contact haemolysin" ("virulence plasmid" product) are responsible for their invasion. In the small intestine this cytotoxin is destroyed by trypsin, therefore Shigella invasion takes place in the large intestine where it also lyses vacuole membranes around the bacteria in colonocytes. Widespread cytopathic alterations of the epithelium with a damage to ribosome and protein synthesis, disturbance of vascular permeability and fluid hypersecretion in the small intestine result from Shiga-like enterotoxin-cytotoxin. Extent of the inflammatory leukocyte response depends on the degree of Shigella invasion and multiplication and the destruction of the epithelium. Damages to the endothelium and blood coagulation system resulting occasionally in the infectious-toxic shock, are associated with Shigella destruction by leukocytes and absorption of lipopolysaccharide endotoxin released by them. Interepithelial lymphocytes especially those containing lysosome-like granules (similar to the blood "natural killers") play an important role in the response to Shigella.

[Invasiveness and cytotoxicity as criteria in assessing Yersinia attenuation]. / Invazivnost' i tsitotoksichnost' kak kriterii otsenki attenuatsii iersinii.

The electron microscopic study of cells HEp-2 and the complex microbiological and morphological study of tissues and organs of guinea pigs and mice infected with the isogenic pairs of Yersinia strains (Y. pseudotuberculosis I and Y. enterocolitica 09) differing in the presence of the calcium-dependence plasmid, as well as Y. pseudotuberculosis mutants resistant to rifampicin, nalidixic acid or crystal violet without this plasmid, have revealed that the invasiveness and cytotoxicity of the infective agents are not directly related to the presence of the above-mentioned plasmid in these bacteria. The use of the quantitative characteristics of virulence, such as penetration ability, intracellular multiplication, dissemination and the formation of degenerative changes, has made it possible to find out that the mutants of Y. pseudotuberculosis I, yielding the negative result in the keratoconjunctivitis test and resistant to the above-mentioned antimicrobial substances, can be arranged in the following order according to the degree of attenuation: rifr mutants--nalr mutants--kvlr mutants. In contrast to Y. pseudotuberculosis I, the loss of the calcium-dependence plasmid by Y. enterocolitica 09 is accompanied by an essential decrease in their invasive and cytotoxic properties, but this relationship is indirect and unstable. The proposed criteria intended for use in the evaluation of the degree of the manifestation of the invasive and cytotoxic properties of bacteria can be useful for the selection of optimally attenuated Yersinia strains showing promise as vaccine strains.

[Characteristics of the interaction of Leptospira with the host organism in the infectious process in golden hamsters]. / Osobennosti vzaimodeistviia leptospir s organizmom khoziaina pri infektsionnom protsesse u zolotistykh khomiakov.

The comparative evaluation of the interaction of L. icterohaemorrhagiae strain P, L. canicola strain CL and L. hebdomadis strain 650 with golden hamster liver and kidney cells is presented. Three variants of the course of Leptospira infection have been distinguished: (1) the hepato-renal (icteric) variant, caused by the adhesion of leptospires to liver cells with the colonization of their surface and the disaggregation of liver-cell complexes and by the accumulation of leptospires in the kidney interstice; as a consequence, parenchymatous hepatitis and nephroso-nephritis develop, which lead to the death of animals; (2) the renal (anicteric) variant, characterized by the absence of the infective agent and lesions in the liver, by adhesion of leptospires to and their colonization of the nephrothelium of the proximal convoluted tubules of the kidneys; in this case some of the animals die because of renal insufficiency and shock, while in the surviving animals prolonged carrier state develops; (3) the intermediate variant, characterized by the initial process of leptospiral adhesion and colonization in the liver and its subsequent progress in the kidneys.

[Interaction of Leptospira with the host's body in the infectious process in guinea pigs]. / Vzaimodeistvie leptospir s organizmom khoziaina pri infektsionnom protsesse u morskikh svinok.

In experiments on guinea pigs the pathogenicity of leptospires is manifested by their adhesion to liver cells, colonization of the surface of these cells, accumulation of leptospires in the renal interstice and their colonization of the nephrothelial surface of proximal convoluted tubules in the kidneys, by toxic microcirculatory disturbances, dystrophy and necrosis of nephrothelial cells. Then the primary toxic action of circulating leptospires, microcirculatory disturbances and hemorrhagic syndrome augment during the colonization of the surface of liver cells, accompanied by their dystrophy and dissociation, as well as by jaundice. The accumulation of leptospires in the renal interstice and their subsequent multiplication on the nephrothelium of the proximal convoluted tubules are responsible for the development of interstitial nephritis and necrotic nephrosis. The persistence of lesions in the liver and kidneys, occurring in some cases in spite of elimination of the infective agent from these organs due to increasing antibody production suggests the toxic action of immune complexes.

[Comparative evaluation of Yersinia interaction with HEp-2 cells]. / Sravnitel'naia otsenka vzaimodeistviia iersinii s kletkami HEp-2.

In experiments on HEp-2 cells, the comparative characterization of the mechanism of invasion and the cytotoxic action of a number of Y. pseudotuberculosis strains, serovar 1, and Y. enterocolitica strains 03 and 09 (24 strains newly isolated from human patients and rodents and 5 laboratory strains at different degrees of attenuation) has been made on the basis of data obtained by optical and electron microscopy, as well as by cytoenzymological analysis. As revealed in these experiments, the invasion of Yersinia into epithelial cells and their capacity for intracellular multiplication depend on the cytotoxicity of the bacteria, most pronounced in Y. pseudotuberculosis, serotype 1, considerably less pronounced in Y. enterocolitica 09, and poorly pronounced (or absent) in Y. enterocolitica 03. Cytopathic changes are manifested by vacuolization, the exocytosis (clasmatosis) of the peripheral cytoplasm, impoverishment in organellae, the formation of autophagosomes, the shriveling of the nuclei and the perinuclear cytoplasm, the rounding of the cells and their separation from the glass surface. The development of these changes is accompanied by the increased activity of phosphatases diffusing into the cytoplasm and by the inhibition of cell respiration and dehydrogenase activity.

[Invasiveness characteristics of the causative agent of pseudotuberculosis]. / Kharakteristika invazivnosti vozbuditelia psevdotuberkuleza.

The comparative characteristics of the invasiveness of Y. pseudotuberculosis, the most important element of its pathogenicity, is given on the basis of the results obtained in testing 57 Y. pseudotuberculosis strains and 23 Y. enterocolitica strains, all of them recently isolated, on experimental models (the monolayer cultures of Hep-2 cells, the enteral inoculation of mice and guinea pigs, the keratoconjunctival test). The invasiveness of Y. pseudotuberculosis has been shown to be manifested immediately after the ir adhesion and accompanied by the multiplication of these microbes in the cytoplasma of Hep-2 cells and, in animal experiments, in the cytoplasma of the epithelial cells of mucous membranes and the macrophages of lamina propria mucosae. The intracellular multiplication leads to the destruction of the layer of Hep-2 cells and, in animal experiments, to the disintegration of the infected cells, the development of Hep-2 cells and, in animal experiments, to the disintegration of the infected cells, the development of erosions and ulcers, purulent lymphadenitis of the regional lymph nodes, generalized infection with multiple abscesses in internal organs. Y. enterocolitica strains under investigation induced neither conjunctivitis, nor enterocolitis in the animals, and in experiments on Hep-2 cells, these strains, having less pronounced adhesive properties, either showed sharply limited adhesiveness without the capacity for intracellular multiplication and cytotoxicity, or proved to be absolutely noninvasive.

[Use of the keratoconjunctival test for determining the virulence of the causative agent of pseudotuberculosis]. / Primenenie keratokon" iunktival'noi proby dlia opredeleniia virulentnosti vozbuditelia psevdotuberkuleza.

When tested in guinea pigs, Y. pseudotuberculosis strains, serovar I (25 strains) and serovar V (1 strain), were found for the first time to be capable of causing keratoconjunctivitis in the animals; the most virulent of these strains caused progressive conjunctivitis and keratitis with generalized infection. The minimum infective dose was 10(4) for conjunctivitis and 10(6) for keratitis. The studied Y. pseudotuberculosis strains, serovars O3 and O9, were found to be incapable of causing conjunctivitis and keratitis. The authors believe that the keratoconjunctival test allows one to evaluate the invasiveness and toxicity of Y. pseudotuberculosis according to the degree of the manifestation and the time of the development of conjunctivitis and keratitis.