[Intranasal co-administration of recombinant streptococcus group B polypeptides and influenza deltaNS1 vaccine].

In the present work, the immunoadjuvant properties of the influenza deltaNS1 vaccine virus after intranasal administration in combination with recombinant GBS polypeptides was tested in mice. According to our data, co-administration of recombinant GBS polypeptides and influenza deltaNS1 vaccine resulted in the increase in the immunogenicity and protective efficacy of bacterial proteins. Combined vaccination with the GBS polypeptides and influenza deltaNS1 vaccine has a potential to be used not only for prophylaxis infections caused by SGB, but also for prevention of the bacterial complications of influenza.

[Recombinant fragments of conservative proteins of group B streptococci as a basis of specific vaccine].

AIM: The study devoted to problem of using of recombinant fragments of group B streptococci (GBS) conservative proteins for induction of immune response against streptococcal infections. Two recombinant polypeptides (ScaAB and-ScpB1) corresponding to immunogenic epitopes of two surface GBS proteins ScaAB and C5a-peptidase, which are presented in other streptococcal species, were studied. The objective of the study was to assess specificity and protective activity of mentioned polypeptides against homologous and heterologous strains of pathogenic streptococci from different groups. MATERIALS AND METHODS: Strains of Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus agalactiae were used in the study. Array of used methods included opsonophagocytic test as well as active and passive protection of experimental animals against streptococcal infection. RESULTS: It was shown that antibodies specific to studied polypeptides opsonized several strains of group A and B streptococci as well as pneumococci. Immunization of mice with ScpB1 polypeptide resulted in more rapid recovery of animals from challenge systemic group B streptococcal infection. Antisera specific to both polypeptides provided passive protection of animals from infection caused either GBS or GAS. CONCLUSION: Obtained data confirm the feasibility to use recombinant fragments of several GBS conservative proteins in vaccine for induction of protection against infections caused by different species of pathogenic streptococci.

[Genetic identification as method of detection of pathogenic and symbiotic strains of enterococci].

Comparative study of 97 cultures of enterococci, including reference highly virulent strain Enterococcus faecalis ATCC 259212, 35 clinical isolates of E. faecium, 58 isolates of E. faecalis, and 3 probiotic strains of E. faecium: Linex (Lek company, Slovenia), SF68 (Bifiform, Denmark), and L3 (Avena, Russia). Thirteen of 93 cultures were isolated from patients treated with probiotic Linex, containing E. faecium (Linex) bacterium. Comparative analysis of cultures on the presence of 8 genes determining virulence (esp, asa1, efaA, cylA, cylM, gelE, sprE, and fsrB) was performed using polymerase chain reaction and testing with antibiotics. It was established that in some cases clinical cultures of enterococci used for analysis carried genes of pathogenicity and were not related to E. faecium (Linex) strain included in composition of the probiotic drug.

[Protective properties of certain external proteins of group B streptococci].

On the basis of genes, which control synthesis of externally localized proteins of group B streptococci (bac and scaAB), recombinant polypeptides P6 and ScaAB were obtained. Data on protective activity of these polypeptides during experimental infection of immunized mice as well as in opsonophagocytic test on cultivated peritoneal macrophages are presented. It has been shown that protective effect of specific antibodies to P6 was dependent from intensity of immune response. Titer of specific IgG to P6 equal 1:25000 was protective for mice during challenge with LD50. During sublethal challenge level of humoral immunity determined both rate of microorganism elimination and degree of decrease of concentration of streptococci in the spleen. Recombinant polypeptide ScaAB also had marked protective activity and protective titer ScaAB-specific IgG was significantly lower compared with the first polypeptide (1:1600). It has been established that both types of antibodies have opsonizing activity against different strains of group B streptococci. Opsonizing properties of antibodies to P6 were restricted to Bac protein-producing streptococci whereas specificity of antibodies to ScaAB was not restricted by type and group borders. Opsonization of both group B and group A streptococci was revealed. It has been established that protective efficacy mediated by antibodies was dependent not only from their opsonizing characteristics but also from availability of protein antigens, which under certain conditions can be shielded by capsular polysaccharide. It has been assumed that vaccine preparation developed on the basis of polypeptides P6 and ScaAB is promising for further research.

[Immunogenicity of modified by dextran recombinant fragment of Bac protein of group B streptococci].

Opportunity to increase of immunogenicity of recombinant polypeptide P6 constructed on the basis of surface protective Bac protein by its chemical conjugation with dextran (D) 40 was studied. 3 preparations with different quantity of protein and polysaccharide components were obtained. Their testing with standard serum showed that antigenic determinants of the polypeptide were preserved although partly enclosed and structure of antigenic determinants did not significantly changed. On the model of subcutaneous immunization of mice it has been shown that two preparations--P6D2 and P6D3--have improved immunological characteristics. Conjugation of polypeptide P6 with dextran let to increase of immune response to P6 and affinity of P6-specific antibodies. Injection of nonconjugated P6 and dextran mixture showed that free dextran is not immunogenic and it suppress synthesis of P6-specific antibodies without effect on their affinity. Intranasal administration of nonconjugated P6 did not lead to P6-specific IgG in serum. After conjugation with dextran polypeptide P6 was recognized as an antigen and stimulated production of small quantity of antibodies. Technological process of chemical binding of protein antigen with polysaccharides, which let to regulate protein and polysaccharide components ratio, can be the effective method to increase immunogenicity of recombinant polypeptides.

[Experimental evaluation of recombinant polypeptides as Streptococcus Group B vaccine].

Recombinant polypeptides corresponding to the conservative N-terminal area of Bac surface protein of group B streptococci (GBS) and having the human IgA binding-site were obtained and evaluated in terms of Immunogenic and protective properties. GBS strain 219, serotype 1 bc, served as the source of chromosomal DNA used for cloning. Three polypeptides P1, P5 and P6 were constructed. Polypeptides P1 and P5 with a molecular weight of 22 kD were coded by practically identical DNA fragments (685 nucleotide pairs) and differed in two aminoacids In their central part. Polypeptide P6 had a molecular weight of 35 kD, The fragment of recombinant Bac protein with a molecular weight of 35 kD was found to have protective properties: when used for the subcutaneous immunization of animals, it stimulated the development of immune response capable, in case of challenge, to induce accelerated elimination of streptococci and the prevention of the mice death. Recombinant fragment P6 of GBS protein Bac may be regarded as a candidate for inclusion into GBS-specific vaccine.

[Preparation of immune sera to group A streptococcus lipoteichoic acid]. / Poluchenie immunnykh syvorotok k lipoteikhoevoi kislote streptokokka gruppy A.

A method is described for the preparation of sera highly active in reactions with Group A Streptococcus lipoteichoic acid. Ultrasound-destroyed biomass of Streptomyces levoris K-3053 strain is used as the antigen. This strain was isolated in studies of soil Streptomyces; it contains sufficient amounts of nonglycosylated glycerolteichoic acid of the first-third types, that is identical in structure to polyglycerophosphate skeleton of Group A Streptococcus lipoteichoic acid.

[Group B streptococci in neonatal pathology: pathogenetic mechanism, diagnosis and prevention]. / Streptokokki gruppy B v neonatal'noi patologii: mekhanizm patogennogo deistviia, diagnostika i profilaktika.

Group B streptococci have recently attracted the attention of researchers as the causative agents of human neonatal disease. They are currently encountered much more frequently than it was believed previously. Various types of adult pathogen carriers have been described; this accounts for the numerous sources and pathways of infection transmission, both vertical and horizontal. The transmission risk depends on many factors, vaginal colonization in the parturient being of special import. The level of the pathogen adhesion to the barrier epithelium is reflective of the tissue sensitivity to infection. Increased sensitivity of the vaginal epithelium to B streptococci adhesion in association with the intake of some contraceptives has been found. The adhesive activity of avirulent streptococci B strains is shown to be higher than in the virulent strains, which is especially important in mixed virus bacterial infections. The streptococcal infection of high mortality is underlain by activation of persisting avirulent streptococci B that manifest their pathogenicity as a result of the virus-specific modifications in the host cell membrane. During 1985-1987, in Leningrad Institute of Gynecology and Obstetrics over 80 strains of streptococci B were isolated, the leading serotypes being Ia/C, Ib/C, II/C, III/R. Only 54% of the studied pregnancies attended with the streptococcus carriage had a favourable neonatal outcome. The strain serotypes from maternal isolates and abortuses fully correlated. Further improvement of the laboratory diagnosis and means of the pathogen and its carriers identification is a current priority.

[The role of fibronectin in the streptococcal adhesion process]. / Rol' fibronektina v protsesse adgezii streptokokkov.

The work shows that fibronectin obtained from human plasma is capable of binding with streptococci of different groups with almost equal effectiveness. Fibronectin bound to bacterial cells inhibits the adhesion of group A streptococci onto vaginal cells, but it produces no effect on the adhesion of group B streptococci. The binding constant of fibronectin 125I is equal to 10(6) -M-1, which indicates that the level of the specificity of interaction is not sufficiently high.

[Fatal synergism of viral-bacterial infections (a model of influenza-streptococcal infections)]. / Leta'lnyi sinergizm virus-bakteria'lnykh infektsii (mode'l: gripp-streptokokk).

A model of virus-bacterial infection involving A (PR-8/34) influenza virus and group B streptococcus is proposed to demonstrate the cyclic manifestations of fatal synergism of the causative agents correlating with either the cyclic detection of influenza virus antigens in the infection focus on administration of avirulent streptococcal Fos4 strain, or with the time-course of activity shown by natural killers on administration of virulent streptococcal Fos8 strain. Based on the presented data on the cyclic character of fatalities, whose dynamics varies only slightly with the biological properties of the second agent, a conclusion has been derived on (1) the simultaneous influence of various factors in the formation of the mechanisms of infection transformation, (2) the capability of the cell receptor apparatus to respond to an external stimulus which is the most important of these mechanisms, and (3) the effects of the biological properties of the causative agents on the fatal effect manifestations.

[Comparative aspects of adhesion of group A and B streptococci to human epithelium]. / Sravnite'lnye aspekty adgezii streptokokkov grupp A i B k épiteliiu cheloveka.

The international and original research data on the adhesion of group A and B streptococci are over-viewed. Based on the conducted studies, a conclusion has been drawn on the polyfactor pattern of pathogenic streptococci adhesions. The polyfactor pattern of adhesion is manifested in (a) different ranges of tissue sensitivity to streptococci adhesion, (b) a correlation between the adhesiveness and particular phenotypes (M(+)-M-; OF(+)-OF- in group A streptococci, TSA(+)-TSA- in group B streptococci), (c) different sensitivity of adhesives to proteolytic enzymes, and (d) interaction with fibronectin. M-protein was found to be involved in specific pyogenic streptococcal adhesion to the pharyngeal epithelium, which opens up new vistas for the search of approaches to the prevention of mucosal colonization. The participation of lipoteichoic acid (LTA) in group A and B streptococci adhesion in different tissues was shown The involvement of proteins in group B streptococcal adhesion was suggested by indirect evidence, which needs to be confirmed by direct isolation of an adhesive. It is suggested, that different quantitative combinations as well as structural organization of protein complexes and LTA in the streptococcus cell wall may determine the strain and species specificity of pathogenic group A and B streptococci interaction with host tissues.

[Dynamics of early morphologic shifts in the bronchopulmonary system in intranasal infection of mice with streptococcus group B]. / Dinamika rannykh morfologicheskikh sdvigov v bronkholegochnoi sisteme pri intranazal'nom zarazhenii myshei streptokokkom gruppy B.

When mice are intranasally infected with avirulent and virulent B streptococci, one may single out 2 phases of microbe interaction with bronchopulmonary tissue: 1) streptococcal adhesion, epithelial detachment and causative agent phagocytosis occur within the first 2 hours; 2) hematogenic phagocytes are involved in the process 5 or more hours later. Unlike avirulent streptococci, virulent ones frequently lead to the formation of destructive foci and are less actively phagocytized. On infection with avirulent strain, the microbes seed from the lung during 24 hours. The phagocytotic index and mean alveolar macrophage destruction values are in excess of the similar values seen in polymorphonuclear leukocytes, becoming lower on day 6 of postinfection.

[Biological properties of Streptococcus group B: the interrelations of the virulence in mice, the adhesion to human epithelial cells and the production of type-specific antigen]. / Biologicheskie svoistva streptokokkov gruppy B: vzaimootnosheniia mezhdu virulentnost'iu dlia myshei, adgeziei k épitelial'nym kletkam cheloveka i produktsiei tipospetsificheskogo antigena.

The results presented in this work confirm the possibility of selecting the subpopulations of group B streptococci by the passage of these microorganisms through mice. This process was accompanied by the accumulation of cells with a high level of type-specific antigen (TSA). The passage of group B streptococci in the presence of type-specific antibodies led to the selection of avirulent microorganisms with low TSA production and high adhesiveness. These data may be considered to be the indirect evidence of the screening effect of TSA contained in the capsule of group B streptococci with respect to the ligand structures of these microbes. This suggestion is confirmed by the behavior of the variants of group B streptococci, obtained in the course of this investigation, on virus-infected tissue when TSA+ strains lost their ability to recognize viral polypeptides serving as receptors for TSA- variants of the streptococci.

[A comparison of 2 methods for determining the hydrophobicity of Streptococcus groups A and B]. / Sravnenie dvukh metodov opredeleniia gidrofobnosti u streptokokkov grupp A i B.

A simple method for the evaluation of the hydrophobic properties of streptococci, pathogenic for humans, by their adherence to polystyrene and a modified method for measuring their hydrophobic properties by their sorption on hexadecane have been developed. The results obtained in the evaluation of the hydrophobic properties of streptococci by these two methods have been compared and the complete correlation of these results in classifying the cultures as hydrophobic and hydrophilic has been shown. For the first time the differences in the hydrophobic properties of different strains of group B streptococci have been established.

[Effect of the influenza A virus on the sensitivity of mice to infection caused by Streptococcus group B]. / Vliianie virusa grippa A na chuvstvitel'nost' myshei k infektsii, vyzvannoi streptokokkami gruppy B.

Study of the capacity of group B streptococci for causing the development of infection in mice has revealed the virulence of the cultures for mice to be determined by the serovar of the streptococcus, the infective dose, and the amount of type-specific polysaccharide. Under the conditions of mixed viral-bacterial infection, influenza A virus was shown to influence the development of bacterial infection in the animals in two ways: to increase the virulence of an avirulent strain and to decrease the pathogenicity of a virulent one in streptococcal monoinfections. Simultaneously with viral infection, the stimulation of the multiplication of an avirulent strain in the lungs of mice was observed, while in the control groups of the animals the elimination of bacteria from the lungs was registered. No additional accumulation of the infective virus in the lungs of mice in the presence of streptococci was found.