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Vacuolizing toxin (VacA) Helicobacter pylori is an important factor of pathogenicity of Helicobacter pylori and a basic marker in the diagnosis of helicobacteriosis and related diseases. A coagulation-based diagnostic test-system was elaborated for the detection of VacA in clinical samples. A fragment of vacA was cloned, for the purpose, in Escherichia coli and expressed in preparative quantities; the coded protein was purified and used in raising the diagnostic serum. The thus designed coagulating test-system was successfully tested under the modeling conditions with clinical samples. Therefore, the designed express method can be used for the invasion-free determination of VacA in patients with gastric and duodenal pathologies.

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The results of the immunophoretic analysis of H. pylori antigenic structure are presented. Along with H. pylori O-antigen, specific surface antigen of acidic nature, relatively thermolabile with characteristics similar to those of K-antigens, was detected. A diagnosticum based on the coagglutination test for the rapid detection of H. pylori specific antigens in the patients' biological fluids (coprofiltrate, saliva) by the noninvasive method was developed. The circulation mode of H. pylori in human body and its correlation with the clinical symptoms of the disease was shown. H. pylori antigens were very frequently detected (in 65 - 83% of cases) in patients with acute bacterial enteric infections: shigellosis, salmonellosis, yersiniosis, campylobacteriosis. The newly developed method seems to be promising for the rapid diagnosis of H. pylori associated infections, for the prolonged monitoring and evaluation of the effectiveness of antibacterial therapy.

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In this investigation for the first time the results of the reaction of coaglutination (RCA) using as an invasive identification method of H.p-antigene- H. p.-markers in patients with duodenal ulcer in comparison with the rapid urease test and bacterioscopy of bioptate are presented. It was determined that RCA is the rapid, sensitive (87.4%) and specific (100%) method of diagnosis. The titer change of specific antigen H.p. in excrement and in saliva reflexes the efficiency of the anti-bacterial therapy.

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The peripheral blood leukocyte migration activity (LMA) was studied in 134 acute dysentery patients and 129 salmonellosis patients by using the in vitro screening assay of cell migration (SACM) from microcultures, stimulated with LPS antigens from a number of enteric pathogens. At the acute period of the disease (days 1-5) in the greater part of the patients (80-90%) the specific acceleration of LMA, later followed by its inhibition, was registered in the presence of the pronounced intoxication and diarrhea syndromes, as well as the intensive circulation of specific antigens of the infective agents in the body (established by the method of the coagglutination test). The established phase fluctuations of LMA correlated with the severity and character of the infectious process. SACM was found to be highly sensitive and specific, convenient, well reproducible and having good prospects for the early diagnosis of enteric infections, including those of mixed etiology.

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Fractions of S.flexneri 2a 516 outer membrane proteins determined by plasmid pSF140 have been shown to possess immunomodulating activity and to be capable of influencing the intensity of hematopoiesis, manifested by the stimulation of endocolony formation, the increase of the amount of splenic colony-forming units in the marrow, the increase of the pool of proliferating splenic colony-forming units of the marrow and their intensive migration into the blood. Outer membrane proteins have been shown to produce an immunostimulating effect on the functional activity of effector B-lymphocytes shortly after their injection. On the contrary, S.flexneri 2a 516/4 pSF140- outer membrane proteins produce a less pronounced effect on hematopoietic stem cells and reproduce unspecific immunostimulating effect on the formation of B-cells, synthesizing antibodies to heterologous antigen.

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The results of the detection of Shiga toxin antigen in culture filtrates of 73 enterobacterial strains by the methods of countercurrent electrophoresis and coagglutination, as well as their correlation with the presence of other factors of virulence, O- and K-antigens, have been analyzed. Sharply pronounced inverse correlation between the capacity of enterobacteria to synthesize Shiga (Shiga-like) toxins and their capacity to synthesize acidic polysaccharide surface-specific K- (Vi-) antigens has been established.

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A new chemical typhoid vaccine containing the complex of surface Vi- and K-antigens has been obtained and experimentally studied. The vaccine has been found to possess high immunogenic and antigenic potency. Typhoid complex vaccine containing K-antigen stimulates the development of anti-infection and postvaccinal complex.

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For the first time different action of S. sonnei strains, opposite in their virulence, on hematopoiesis and the functional activity of T- and B-lymphocytes has been shown. The hematopoiesis-disturbing action of virulent shigellae is manifested by their capacity, more pronounced than similar capacity of an avirulent (vaccine) strain, for stimulating the processes of endo- and exocolony formation, the proliferation of hematopoietic stem cells and their migration to the blood. The effect produced by shigellae on T-cell-mediated immune response is manifested by the suppression of macrophage migration and its subsequent activation, whose manifestations and duration depend on the virulence of S. sonnei strains under study. The modulating effect of S. sonnei on B-cell-mediated immune reactions is manifested by the inhibiting action of S. sonnei virulent strain and the stimulating action of S. sonnei vaccine strain on the formation of antibody-producing cells synthesizing S. sonnei lipopolysaccharide antibodies shortly after the injection of shigellae. The results of this study indicate that S. sonnei virulent and avirulent (vaccine) produce multifunctional and differing effects on cell-mediated immune reactions, these processes being dependent on the virulence of shigellae and their individual specific antigens.

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Acute and chronic toxicity of a new chemical typhoid preparation containing the complex of surface Vi- and K-antigens has been studied. The study has revealed that the preparation, when introduced subcutaneously and intravenously in immunizing doses in a single injection or in multiple injections, produces no toxic effect on the organs and tissues of experimental animals. In experiments of chronic toxicity the microscopic study has shown pronounced hyperplasia of the lymphoid system with enhanced macrophage reaction in the spleen, thymus, mesenteric lymph nodes and Peyer's patches in the small intestine.

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The influence of S. sonnei ribosomal vaccine on hematopoiesis, T- and B-cell-mediated immune reactions has been studied in the course of the development of experimental vaccinal process. The vaccine stimulated hematopoiesis, that was characterized by a dose-dependent increase in colony-forming units in the spleen (CFUs), a rise in CFUs in the blood and bone marrow and an increase in the pool of proliferating stem cells in bone marrow, shortly after injection. A pronounced immunostimulating effect of the vaccine on the formation of antibody-producing cells (APC) to heterologous antigen (sheep red blood cells) in the spleen has been established, and the vaccine has also been found to stimulate, though to a lesser extent, APC synthetizing specific antibodies to S. sonnei LPS. The injection of S. sonnei ribosomal vaccine influences the functional activity of effector T-cells; in its turn this phenomenon produces phasic changes in the migration activity of spleen cells in the presence of specific LPS and surface polysaccharide antigen of S. sonnei in phase I.

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The results of experiments, indicating the development of cell-mediated delayed hypersensitivity (DH) skin reaction, its dependence on the virulence of Shigella flexneri 2a, the dose and the character of the antigen used for testing the reaction, are presented. One of the immunologically active components of S. flexneri virulent strain 2a No. 516 is a biologically active thermolabile factor detected in filtrate and supernatant fluid. These data suggest that the immunosuppressive action of the virulent strain is probably linked with the function of T-suppressors affecting the reaction at the period of its development (the induction phase). S. flexneri avirulent strain produced no such effect, developing DH being seemingly sufficient for activating T-cell-mediated immune response.

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The antigenic composition of 24. Y. pseudotuberculosis newly isolated and reference strains, 7 Y. enterocolitica strains, as well as Y. pestis vaccine strain EV, has been studied by the method of immunoelectrophoresis in agar. The antigenic composition of these bacteria has been found to be complicated and to comprise not less than 8-11 antigens, and among them nonspecific protein antigens common for enterobacteria, the common generic antigen, the antigen common with Y. pestis, as well as O-antigens specific for each serovar are identified. Immunoelectrophoretic study has shown the possibility of Y. pseudotuberculosis O-antigen, serovar I, with Salmonella sera, serogroup A, and Y. enterocolitica 09 with brucellar and cholera sera.

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The electron microscopic dynamic study of the interaction of S. flexneri virulent strain 2a and S. flexneri avirulent strain, genetically related to strain 2a and having the same antigenic structure, with peritoneal macrophages of CBA mice at an early period showed differences in the cytotoxic action of these strains. Even at the early period of the interaction between macrophages and virulent shigellae structural changes were observed in macrophages: ruptures in the membranes of parasitophore phagosomes, the vacuolization of the cytoplasm, the destruction of mitochondria. These changes were indicative of the early cytotoxic action of shigellae belonging to the virulent strain. In macrophages infected with avirulent shigellae the manifestations of this cytotoxicity were less pronounced and appeared later than in macrophages infected with S. flexneri virulent strain.

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Investigations with a view to the development and trial of a slide coagglutination test system for the detection of specific Salmonella typhi antigens have been made. As a result, diagnostic agents with sensitivity to group D Salmonella lipopolysaccharides and Vi-antigen, equal to 1 X 10(-5) to 1 X 10(-6) g/l, have been obtained. Specimens of saliva, urine and fecal filtrates from 61 adult patients with bacteriologically confirmed typhoid fever and 54 practically healthy persons have been studied. The coagglutination test has been positive with specimens from 90 +/- 4% of typhoid fever patients and, within the first 5 days of the disease, with those from 85 +/- 7% of such patients. The slide coagglutination test with saliva specimens has been found to be more informative than that with urine specimens. The data obtained in these investigations indicate that the slide coagglutination test is highly sensitive and specific, which offers good prospects for its use as a simple, economic and demonstrative method for the early tentative diagnosis of typhoid fever.

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The effect of S. flexneri virulent and avirulent (vaccine) strains 2a on the cytoplasmic membrane of mouse macrophages has been studied by evaluating the action of these bacteria on the activity of 5-nucleotidase. The dynamics of the activity of 5-nucleotidase after the introduction of both virulent and avirulent strains has a phasic character with alternating rises and falls in the activity of this enzyme in comparison with the control. S. flexneri vaccine strain produces mainly a stimulating effect on the functional activity of peritoneal macrophages in mice, which is confirmed by a decrease in the activity of 5-nucleotidase; on the contrary, S. flexneri virulent strain- has mainly an inhibiting effect on the functional activity of peritoneal macrophages, which is confirmed by an increase in the activity of 5-nucleotidase in these cells. The comparative study of changes in the activity of 5-nucleotidase, following the introduction of S. flexneri, in mice, previously immunized with smallpox vaccine, and in intact mice has shown that the use of animals immunized with smallpox vaccine in the study of metabolic characteristics may lead to distortions in the results of the experiment.

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