[Sialic acids and O-acetyl groups as markers of biological activity of microbial polysaccharides in plague and cholera agents].

AIM: To determine sialic acids and O-acetyl groups content in Yersinia pestis and Vibrio cholerae antigens in order to establish their association with biological activity. MATERIALS AND METHODS: The following antigens of Y. pestis EV NIIEG strain--capsular antigen (F1), major somatic antigen (MSA), lipopolysaccharide (LPS), Pla-protease, allergen pestin PP--as well as O-antigens (O-AG) of V. cholerae serogroups O1 and O139 were used in the study. Sialic acids were identified by the thiobarbituric method, and O-acetyl groups--according to Alicino. Specific polysaccharides in the MSA and O-antigens were detected by the immunodiffusion assay. RESULTS: Sialic acids were found in LPS, Pla-protease, allergen pestin PP, and all cholera O-AG; their absence was demonstrated in MSA and F1. O-acetyl groups were identified in cholera O-AG of both studied serogroups as well as in LPS, Pla-protease, MSA and pestin PP of Y. pestis. Tendency to correlation between O-acetyl groups content in MSA and serological activity titer was observed. CONCLUSION: Sialic acids and O-acetyl groups identified in carbohydrate-containing antigens of Y. pestis and V. cholerae could be characterized as reaction-active markers of pathogenetic mechanisms of cholera and plague infections as well as immunochemical activity of microbial polysaccharides.

[Various physico-chemical properties of the Yersinia pestis capsular protein]. / Nekotorye fiziko-khimicheskie osobennosti kapsul'nogo belka chumnogo mikroba.

Some properties of the structure of Y. pestis capsular antigen macromolecules have been studied. The aminoacid composition of F1 protein, the aminoacid sequence of the N-terminal fragment of antigen polipeptide chain were determined. Some peculiarities in the dissociation of capsular antigen macromolecules have been studied. The formation of the product resulting from unterminated thermodissociation of F1 protein oligomeric form, consisting of four subunits, has been registered. The aspects of F1 protein association are discussed.

[Interleukin-1 induction by different antigens and strains of Yersinia pestis bacteria in immunized mice]. / Induktsiia interleikina-1 razlichnymi antigenami i shtammami bakterii Yersinia pestis u immunizirovannykh myshei.

In this work the influence of Y. pestis antigens (capsular antigen, mouse toxin, lipopolysaccharide, pesticin), as well as the products of gene expression localized on three Y. pestis resident plasmids, have been studied. Capsular antigen and some antigens coded for by plasmid pCad have been shown to possess essential activity in the initiation of the synthesis of interleukin-1. Mouse toxin and the products of plasmid pPst produce the opposite effect.

[A comparative cytofluorimetric analysis of the blood leukocytes in guinea pigs exposed to the phospholipase D and antigens of the causative agent of plague]. / Sravnitel'nyi tsitofliuorimetricheskii analiz leikotsitov krovi morskikh svinok pri vozdeistvii fosfolipazy D i nekotorykh antigenov vozbuditelia chumy.

The influence of Y. pestis phospholipase D on the physiological state of leukocytes in the blood of guinea pigs was studied in vivo by flow impulse fluorometry with the use of fluorochrome acridine orange. During the first hours of observation the intensity of leukocyte fluorescence increased due to a rise in the number of polymorphonuclear leukocytes and changes in the permeability of cell membranes. Further changes in the intensity of the fluorescence of the material under study after 24 hours of observation occurred due to the appearance of activated lymphocytes in the blood stream. The processes normalized by day 21. The reaction of blood leukocytes to phospholipase D was specific in comparison with the reaction to capsular antigen, "mouse" toxin, lipopolysaccharide and the main somatic antigen.

[The role of T-suppressors in the formation of plague immunity in mice]. / Rol' T-supressorov v formirovanii protivochumnogo immuniteta u myshei.

Antiplague immunization of mice causes an increase in the number of T-suppressors in their thymus and spleen; this increase is especially pronounced after injection of a low-immunogenic dose of the vaccine strain. T-suppressors specific to Yersinia pestis antigens were detected in the thymus on day 3 after a single injection and on day 14 after two injections of the vaccine strain.

[The effect of different Yersinia pestis antigens on the cellular link in immunity]. / Izuchenie vliianiia razlichnykh antigenov Yersinia pestis na kletochnoe zveno immuniteta.

Immunization with live plague vaccine has been shown to give no protection to thymectomized mice from subcutaneous challenge with Y. pestis virulent strain. Under the action of the vaccine or individual Y. pestis antigens (fraction I) the functional and morphological activation of thymocytes and macrophages is observed, more pronounced in C57BL/6 mice and less pronounced in CBA mice. Y. pestis antigenic preparations (fractions I and II, pesticin) act as T-cell mitogens and are thus capable of inducing the in vitro proliferation of thymocytes. At the same time the in vivo action of fraction II induces a decrease in the level of lymphocytes in the peripheral blood of mice and the destruction of lymphocytes in their thymus and spleen.

[Comparative incidence of detection of specific antibodies to Yersinia pestis capsular antigen and lipopolysaccharide in humans immunized with pest vaccine]. / Sravnitel'naia chastota obnaruzheniia spetsificheskikh antitel k kapsul'nomu antigenu i lipopolisakharidu Yersinia pestis u privitykh chumnoi vaktsinoi liudei.

Two to 8 years after vaccination, specific antibodies to capsular antigen (F1) and lipopolysaccharide (LPS) are found in the blood sera of but 10 to 20% of subjects 1-4 times epicutaneously immunized with live antipest vaccine. Only regular continuous (for at least 7-15 years) antipest vaccination leads to the production of antibodies to the main antigens of Yersinia pestis, detectable in remote periods in 75.9 +/- 4.5% of vaccinees. It is noteworthy that the number of positive responses and titer of antibodies to LPS is appreciably higher than to F1. Detection of antibodies to Y. pestis is recommended for the retrospective diagnosis of pestis in both humans and animals in natural foci of this infection. Competitive enzyme immunoassay on nitrocellulose membranes with monoclonal antibodies is to be preferred for the purpose.

[The effect of Yersinia pestis antigens and strains on the level of lymphocyte blast transformation]. / Vliianie antigenov i shtammov chumnogo mikroba na uroven' blasttransformatsii limfotsitov.

Lymphocytic blast-cell transformation (LBCT) is shown to be related both to the genotype of a macroorganism and to the genetically determined expression of individual antigens by the plague microbe. The correlation of LBCT with the level of antiinfectious resistance suggests that this index is of high informative value and that it can be effectively used for testing the cellular immunity and the characteristically biological properties of the plague causative agent and its antigens.

[Sensitivity to mouse toxin and level of macrophage 5-nucleotidase activity]. / Chuvstvitel'nost' k myshinomu toksinu i uroven' aktivnosti 5-nukleotidazy makrofagov.

It is shown that immunomodulator of bacterial origin salmozan causes alternations of sensitivity to mouse toxin in mice CBA. A correlation exists between the sensitivity to mouse toxin and the level of 5-nucleotidase of peritoneal exudate macrophages.

[Characteristics of the polysaccharide-containing somatic antigens isolated from the K-1 strain of the plague microbe and its antibiotic-resistant variants]. / K kharakteristike polisakharidsoderzhashchikh somaticheskikh antigenov, izolirovannykh iz shtamma K-1 chumnogo mikroba i ego antibiotikoustoichivykh variantov.

Immunochemical analysis of 2 polysaccharide-containing structures of the lypopolysaccharide of the plague causative agent (main somatic antigen and lipopolysaccharide) isolated from K-1 strain and a number of its antibiotic resistant mutants was carried out. It was shown that development of resistance to streptomycin alone or its combination with monomycin did not cause detectable changes in the monosaccharide composition and serological properties of the cultures tested. More significant changes associated with development of complex resistance, i.e. K-1 (Strr leads to Penr leads to Tetr) were accompanied by a decrease in the content of hexozamine and serological activity of the main somatic antigen determining the O-specificity of the lipopolysaccharide. Defective changes in the monosaccharide composition and serological properties of both the main somatic antigen and the polysaccharide were observed in the yellow variant of the streptomycin resistant mutant K-1.

[Effect of plague microbe fraction 1 protein-polysaccharide complex and pure protein on metabolic parameters of macrophages]. / Vliianie belkovopolisakharidnogo kompleksa i chistogo belka fraktsii 1 chumnogo mikroba na metabolicheskie pokazateli makrofagov.

The investigation reveals different influence of the plague microbe's fraction 1 polysaccharide-protein complex and of it's purified protein on the 5'-nucleotidase activity and on the chemiluminescence response of peritoneal macrophages. Both of these metabolic indexes were found to be dependent on the dose of fraction 1 and duration of time till examination.