Proteome-wide identification of epitope-based vaccine candidates against multi-drug resistant Proteus mirabilis.

Proteus mirabilis is one of the important pathogens of urinary tract and exhibits resistance to multiple drugs. Development of vaccine tends to be the most promising and cost-effective remedy against the said pathogen. Herein, we implement a combinatorial approach for screening proteins harboring potential broad-spectrum antigenic epitopes in the proteome of P. mirabilis. The targets are host non-homologous, essential and virulent, and have localization in the extracellular and outer membrane. Immuno-informatics revealed antigenic, surface exposed and broad-spectrum B-cell derived T-cell epitopes for three membrane usher family candidates: AtfC, PMI2533 and PMI1466, which could evoke a substantial immune response. Protein-protein interactions of targeted three proteins have shown their involvement in biologically significant pathways indispensable for the growth and survival of the pathogen. The antigenic epitopes are conserved among all completely annotated strains and docked deeply in the binding cavity of the most prevalent allele-DRB1*0101 in human population. Future work is necessary to characterize the shortlisted proteins and epitopes for immune protection in animal models.

GlpC gene is responsible for biofilm formation and defense against phagocytes and imparts tolerance to pH and organic solvents in Proteus vulgaris.

Biofilm-forming bacteria are highly resistant to antibiotics, host immune defenses, and other external conditions. The formation of biofilms plays a key role in colonization and infection. To explore the mechanism of biofilm formation, mutant strains of Proteus vulgaris XC 2 were generated by Tn5 random transposon insertion. Only one biofilm defective bacterial species was identified from among 500 mutants. Inactivation of the glpC gene coding an anaerobic glycerol-3-phosphate dehydrogenase subunit C was identified by sequence analysis of the biofilm defective strain. Differences were detected in the growth phenotypes of the wild-type and mutant strains under pH, antibiotic, and organic solvent stress conditions. Furthermore, we observed an increase in the phagocytosis of the biofilm defective strain by the mouse macrophage RAW264.7 cell line compared to the wild-type strain. This study shows that the glpC gene plays an important role in biofilm formation, in addition to imparting pH, organic solvent, and antibiotic tolerance, and defense against phagocytosis to Proteus sp. The results further clarified the mechanism of biofilm formation at the genomic level, and indicated the importance of the glpC gene in this process. This data may provide innovative therapeutic measures against P. vulgaris infections; furthermore, as an important crocodile pathogen, this study also has important significance in the protection of Chinese alligators.

Structure of the alanopine-containing O-polysaccharide and serological cross-reactivity of the lipopolysaccharide of Proteus vulgaris HSC 438 classified into a new Proteus serogroup, O76.

The O-polysaccharide was isolated by mild acid hydrolysis of the lipopolysaccharide of Proteus vulgaris HSC 438, and the following structure was established by chemical methods and one- and two-dimensional (1)H and (13)C NMR spectroscopy: →3)-ß-d-Quip4NAlo-(1→3)-α-d-Galp6Ac-(1→6)-α-d-Glcp-(1→3)-α-l-FucpNAc-(1→3)-ß-d-GlcpNAc-(1→, where d-Qui4N stands for 4-amino-4,6-dideoxy-d-glucose and Alo for N-((S)-1-carboxyethyl)-l-alanine (alanopine); only about half of the Gal residues are O-acetylated. This structure is unique among the Proteus O-polysaccharides, and therefore it is proposed to classify P. vulgaris HSC 438 into a new Proteus serogroup, O76. A serological cross-reactivity of HSC 438 O-antiserum and lipopolysaccharides of some other Proteus serogroups was observed and accounted for by shared epitopes on the O-polysaccharides or lipopolysaccharide core regions, including that associated with d-Qui4NAlo.

[Immunovac-VP-4 for prevention of acute respiratory diseases in children's communities].

AIM: Assessment of prophylactic effect of Immunovac-VP-4 against acute respiratory diseases (ARDs) in collectives of children. MATERIALS AND METHODS: Immunovac-VP-4 was used for prophylaxis of ARDs in communities of children (daycare centers, boarding school). During 3 consecutive controlled studies performed during peak incidence of epidemic influenza and ARD (1st study) and during pre-epidemic period (2nd and 3rd studies) the incidence of ARDs was studied in groups of vaccinated and non-vaccinated children. Criteria for assessment of ARDs incidence and their severity were as follows: number of ARD episodes per child, number of children with recurrent episodes of ARD during period of follow-up, duration of ARDs, and number of children with bacterial complications (bronchitis, otitis, etc.). Effect of intervention on immunologic parameters was assessed on levels of sIgA, IgG, IgA, and antibody titers in saliva. Schedule of vaccine administration was 3 daily intranasal and 6 - 9 oral administration of the vaccine with 3 - 4 days interval. RESULTS: Results of all three studies were virtually the same: decrease of number of ARD episodes and their duration; 3.1-fold reduction of number of children with recurrent infections during 14 months of follow-up, and 10.9--12-fold reduction during first 7 months of follow-up; decrease of bacterial complications rate (1.9% in children in intervention group, 11.9%--in control group). Increase of total immunoglobulin level and antibody titers to antigenic components of the vaccine from low baseline level was observed in saliva of vaccinated children. CONCLUSION: Immunovac-VP-4 results in enhanced and prolonged prophylactic effect on ARDs incidence and recommended for building of optimal system of prevention of polyetiologic complex of ARDs.

[Immunovac-VP4 vaccine used in complex allergen-specific immunotherapy of patients with hay fever].

AIM: Assessment of clinical and immunological effects of use of bacterial therapeutic polycomponent vaccine Immunovac-VP4 for allergen-specific immunotherapy (ASIT) of hay fever. MATERIALS AND METHODS: Five doses of Immunovac-VP4 vaccine consisted of antigens of opportunistic bacteria was used and administered by nasal-oral route. ASIT was performed with standard water-saline solution of allergens according to defined schedule. Sixty-nine patients with season rhinoconjunctivitis, asthma and their combinations were included in the study and divided to two groups. Skin scarification test was performed, total level of serum IgE, IgG4 and IgE to pollen allergens were measured by ELISA. Also, questionnaire was sent to patients yearly. RESULTS: Administration of bacterial therapeutic vaccine Immunovac-VP4 before start of ASIT resulted in marked clinical and immunological effect. In group of patients receiving combination therapy compared to control group, 8.5 times lower incidence of acute respiratory infections was registered. According to results of analysis of patients' questionnaires after 7 years, effectiveness of therapy was 90% that points to achievement of prolonged remission after completion of ASIT course. CONCLUSION: Utilization of natural ligands of Toll-like receptors is a perspective direction for development of new immunotherapeutic strategies for treatment of allergic diseases.

[The autoagglutination factor of plague pathogen--cross-reacting antigen].

An antigen similar to the autoagglutination factor (AF) of plague pathogen in immunochemical specificity was sought in 22 bacterial species. For this, an immunoglobulin anti-AF diagnosticum that is the sheep erythrocytes sensitized with rabbit immune serum to the AF preparation isolated from the plasmid-free variant of the Yersinia pestis strain EV76. The bacteriological study applying a passive hemagglutination assay revealed AF-like antigens not only in all study strains (n = 30) of Y. pestis, but also in Yersinia pseudotuberculosis, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Proteus vulgaris. These bacteria were used to prepare AF = like antigen preparations that reacted with rabbit anti-AF serum in dot blot immunoassay. Also, as Y. pestis, AF-like antigens in polyacrylamide gel were detected as multiple protein bands that differed in mobility in Yersiniae and heterologous bacteria. Differences were found in the properties of AF-line antigens of 5 species of bacteria (sensitivity to temperature and formalin, binding to the cell surface, which enabled differentiation of serological reactions caused by AP-like antigens of other bacteria. Thus, Y. pestis AF is a cross-reacting antigen that, despite its immunochemical similarity with AF-like antigens of other bacteria, was ascertained to differ from them in properties. The findings are of interest for searching for new diagnostic tests to detect the Cafl- strains of the plague pathogen and for differentiating the causative organisms of plague and pseudotuberculosis.

Leukocyte antimicrobial function in patients with leprosy.

Patients with lepromatous leprosy are unresponsive to lepromin skin-test material and possess defective lymphocyte function in vitro, including impaired mitogenesis in response to antigens of Mycobacterium leprae. It has been claimed that their macrophages cannot digest M. leprae in vitro; such a defect could explain both lepromin nonreactivity and impaired lymphocyte function on the basis of failure of the afferent limb of the immune response (i.e., defective macrophage "processing" of M. leprae). The present studies indicate that macrophages from patients with lepromatous and tuberculoid leprosy and from normal donors do not differ in their ability to digest heat-killed M. leprae in vitro, or in their ability to sustain the viability of M. leprae in tissue culture; that monocytes, macrophages, and polymorphonuclear leukocytes of leprosy patients and controls possess equivalent microbicidal activity against Listeria monocytogenes, Escherichia coli, Proteus vulgaris, Staphylococcus aureus, and Candida albicans; and that polymorphonuclear leukocytes from patients with lepromatous leprosy iodinate ingested bacteria normally. Whether the basic immune defect leading to the development of lepromatous leprosy resides in the lymphocyte or in the macrophage remains to be determined. However, the present study shows that phagocytic cells from patients with either principal form of leprosy function normally in a variety of sophisticated tests of antimicrobial function.

Serological classification and epitope specificity of Proteus vulgaris TG 251 from Proteus serogroup O65.

INTRODUCTION: Proteus rods are currently subdivided into five named species, i.e. Proteus mirabilis, P. vulgaris, P. penneri, P. hauseri, and P. myxofaciens, and three unnamed Proteus genomospecies 4 to 6. Based on the serospecificity of the lipopolysaccharide (LPS; O-antigen), strains of P. mirabilis and P. vulgaris were divided into 49 O-serogroups and 11 additional O-serogroups were proposed later. About 15 further O-serogroups have been proposed for the third medically important species, P. penneri. Here the serological classification of P. vulgaris strain TG 251, which does not belong to these serogroups, is reported. Serological investigations also allowed characterization of the epitope specificity of its LPS. MATERIALS AND METHODS: Purified LPSs from five Proteus strains were used as antigens in enzyme immunosorbent assay (EIA), SDS/PAGE, and Western blot and alkali-treated LPSs in the passive immunohemolysis (PIH) test, inhibition of PIH and EIA, and absorption of the rabbit polyclonal O-antisera with the respective LPS. RESULTS: The serological studies of P. vulgaris TG 251 LPS indicated the identity of its O-polysaccharide with that of P. penneri O65. The antibody specificities of P. vulgaris TG 251 and P. penneri O65 O-antisera, were described. CONCLUSIONS: P. vulgaris TG 251 was classified to the Proteus O65 serogroup. Two disaccharide-associated epitopes present in P. vulgaris TG 251 and P. penneri O65 LPSs are suggested to be responsible for cross-reactions with three heterologous Proteus strains.

Structure of the glycerol phosphate-containing O-polysaccharides and serological studies of the lipopolysaccharides of Proteus mirabilis CCUG 10704 (OE) and Proteus vulgaris TG 103 classified into a new Proteus serogroup, O54.

O-Polysaccharides were obtained from the lipopolysaccharides of Proteus mirabilis CCUG 10704 (OE) and Proteus vulgaris TG 103 and studied by chemical analyses and one- and two-dimensional (1)H and (13)C nuclear magnetic resonance spectroscopy, including rotating-frame nuclear Overhauser effect spectroscopy, H-detected (1)H,(13)C heteronuclear single-quantum spectroscopy and (1)H,(31)P heteronuclear multiple-quantum spectroscopy experiments. The Proteus mirabilis OE polysaccharide was found to have a trisaccharide repeating unit with a lateral glycerol phosphate group. The Proteus vulgaris TG 103 produces a similar O-polysaccharide, which differs in incomplete substitution with glycerol phosphate (c. 50% of the stoichiometric amount) and the presence of an O-acetyl group at position 6 of the 2-acetamido-2-deoxygalactose (GalNAc) residue. These structures are unique among the known bacterial polysaccharide structures. Based on the structural and serological data of the lipopolysaccharides, it is proposed to classify both strains studied into a new Proteus serogroup, O54, as two subgroups, O54a,54b and O54a,54c. The serological relatedness of the Proteus O54 and some other Proteus lipopolysaccharides is discussed.

Structures and serology of the O-antigens of Proteus strains classified into serogroup O17 and former serogroup O35.

INTRODUCTION: Bacteria of the genus Proteus are facultative pathogens which commonly cause urinary tract infections. Based on the serological specificity of the O-chain polysaccharide of the lipopolysaccharide (O-polysaccharide, O-antigen), strains of P. mirabilis and P. vulgaris have been classified into 60 serogroups. Studies on the chemical structure and serological specificity of the O-antigens aim at the elucidation of the molecular basis and improvement of the serological classification of these bacteria. MATERIALS AND METHODS: The O-polysaccharide was prepared by acetic acid degradation of the lipopolysaccharide isolated from dried bacterial mass of each strain by hot phenol/water extraction. (1)H- and (13)C-NMR spectroscopy was used for structural studies. Serological studies were performed with rabbit O-antisera using enzyme immunosorbent assay, passive hemolysis test, and the inhibition of reactions in these assays as well DOC-PAGE and Western blot. RESULTS: Four Proteus strains belonging to serogroups O17 and O35 were found to possess similar O-polysaccharide structures, in particular having the same carbohydrate backbone built up of tetrasaccharide repeating units. However, they differ in the presence or absence of additional substituents, such as phosphoethanolamine in P. mirabilis O17 and glucose in P. penneri O17, as well as in the pattern and degree of O-acetylation of various monosaccharide residues. Serological studies also showed close relationships between the O-antigens studied. CONCLUSIONS: Based on these data it is proposed to reclassify strain P. mirabilis PrK 61/57, formerly representing the O35 serogroup, into the serogroup O17 in the Kauffman-Perch classification system of Proteus.

Characterization and serological classification of O-specific polysaccharide of Proteus mirabilisTG 276-90 from Proteus serogroup O34.

INTRODUCTION: Gram-negative bacteria of the genus Proteus from the family Enterobacteriaceae are currently divided into the five species P. mirabilis, P. vulgaris, P. penneri, P. hauseri, and P. myxofaciens and three unnamed Proteus genomospecies 4, 5, and 6. They are important facultative human and animal pathogens which, under favorable conditions, cause mainly intestinal and urinary tract infections, sometimes leading to serious complications such as acute or chronic pyelonephritis and the formation of bladder and kidney stones. In this study we report on the serological properties of the lipopolysaccharide (LPS) of P. mirabilis TG 276-90, whose O-polysaccharide chemical structure was described earlier. MATERIALS AND METHODS: LPS and alkali-treated LPS of a few serologically related Proteus strains and O-antisera against P. mirabilis TG 276-90 and CCUG 4669 (O34) were used. Serological characterization of P. mirabilis TG 276-90 O-specific polysaccharide was done using enzyme immunosorbent assay, passive immunohemolysis test (PIH), inhibition of these tests, SDS/PAGE and Western blot techniques, absorption of rabbit polyclonal O-antisera, and repeated PIH test. RESULTS: Structural and serological investigations showed that the O-polysaccharides of P. mirabilis TG 276-90 and P. vulgaris O34 are identical and that their LPSs differ only in epitopes in the core part. Therefore these two strains could be classified into the same Proteus O34 serogroup. CONCLUSIONS: The serological data showed that the beta-D-GalpNAc-(1--> 4)-alpha-D-GalpNAc disaccharide is an important epitope of the P. mirabilis TG 276-90 and P. vulgaris O34 LPSs, shared by the P. mirabilis O16 and P. vulgaris TG 251 LPSs. It is responsible for cross-reactions with P. mirabilis TG 276-90 and P. vulgaris O34 O-antisera.

Structures of the O-antigens of Proteus bacilli belonging to OX group (serogroups O1-O3) used in Weil-Felix test.

Structures of the O-specific polysaccharide chains of lipopolysaccharides from Proteus group OX strains (serogroups O1-O3) used as antigens in Weil-Felix test for diagnosis of rickettsiosis, were established. From them, the acid-labile polysaccharide of Proteus vulgaris OX19 (O1) is built up of the following branched pentasaccharide repeating units connected via a phosphate group: [structure in text] where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose (N-acetylquinovosamine). The basis of serospecificity of the Proteus group OX antigens and their cross-reactivity with human anti-rickettsial antibodies is discussed.

Agglutinin response to bacterial infection in acute exacerbations of chronic bronchitis.

Agglutinin titres to Haemophilus influenzae, Streptococcus pneumoniae, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Proteus vulgaris in the serum of patients with acute exacerbations of chronic bronchitis, patients producing mucoid sputum, and healthy controls were determined. Serological evidence of infection with H. influenzae was found in 38 of 57 patients with acute exacerbations, and Str. pneumoniae infection in 10 of the 57 patients, but was generally absent from healthy control subjects and from patiens producing mucoid sputum. No serological evidence of infection with other organisms named above was found to be associated with exacerbations of chronic bronchitis. Ten patients with acute exacerbations were without serological evidence of infection by any of the bacteria tested.

A highly discriminatory multi-typing scheme for Proteus mirabilis and Proteus vulgaris.

Strains of Proteus mirabilis and P. vulgaris isolated in England, Scotland and Sweden were characterised by proticine production-proticine sensitivity (P-S) typing, O serotyping and Dienes typing methods. The determinants of O antigenicity were independent of those determining proticine production and proticine sensitivity. Because of this independence, the combination of P-S typing and O serotyping for the analysis of the 133 serotypable strains separated them into 81 distinct types whereas P-S typing and O serotyping methods alone separated them into only 56 and 19 types respectively. There was a relationship between the Dienes type and the P-S type; the determinants of Dienes compatibility were the proticine production-proticine sensitivity characters. The determinants of O antigenicity appeared to play no role in the Dienes reaction. Some strains that were indistinguishable by P-S typing and O serotyping methods were distinguished by Dienes typing.

Involvement of nitric oxide donor compounds in the bactericidal activity of human neutrophils in vitro.

The bactericidal activity of human neutrophils against extracellular and facultatively intracellular bacteria was studied in the presence of the nitric oxide (NO) donors sodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), a molsidomine metabolite. SNP and molsidomine are drugs commonly used as nitrovasodilators in coronary heart disease. It is demonstrated here that the NO donor compounds themselves did not affect the viability and survival of the bacterial strains tested. Neither SNP nor SIN-1 had any effect on the process of bacteria ingestion. In contrast, NO donors enhanced the ability of neutrophils to kill Escherichia coli, Proteus vulgaris and Salmonella Anatum. However, strains differed in their susceptibility to SNP- and SIN-1-mediated killing by neutrophils. Removal of the superoxide anion reduced the bactericidal activity of SNP- and SIN-1-treated neutrophils against E. coli and S. Anatum. This suggests that the NO derivatives formed in the reaction of NO generated from donors with the reactive oxygen species released by phagocytosed neutrophils potentiate the bactericidal activity of human neutrophils in vitro. The above original observation discussed here suggests clinical significance for the treatment of patients with nitrovasodilators in the course of coronary heart disease therapy.

Structure of the O-specific polysaccharide of Proteus vulgaris O37 and close serological relatedness of the lipopolysaccharides of P. vulgaris O37 and P. vulgaris O46.

The O-specific polysaccharide (O-antigen) of the lipopolysaccharide (LPS) of Proteus vulgaris O37 was studied by (1)H and (13)C nuclear magnetic resonance spectroscopy before and after O-deacetylation and found to be structurally similar to that of P. vulgaris O46 studied earlier. The two polysaccharides have the same carbohydrate backbone and differ in the position and number of the O-acetyl groups only. Studies with O-antisera against the two strains using passive hemolysis test, enzyme immunosorbent assay, and Western blot revealed close serological relatedness of the LPSs of P. vulgaris O37 and O46. The O-acetyl groups were found to be of little importance for manifesting the O-specificity but to interfere with binding of anti-P. vulgaris O37 serum to P. vulgaris O46 antigen. Based on the data obtained, it was proposed to combine the strains studied in one Proteus serogroup O37 as subgroups O37a,37b and O37a,37c. A cross-reactivity of O-antisera against P. vulgaris O37 and O46 was observed with LPSs of three more Proteus strains, which could be substantiated by the presence of a common disaccharide fragment in the O-antigens.

Titres of antibodies to gut-derived antigens in patients with chronic schistosomiasis mansoni.

Serum titres of antibodies against six intestinal, one ubiquitous and one non-intestinal bacteria were determined in patients with severe hepatosplenic schistosomiasis mansoni, with light intestinal schistosomiasis and in normal subjects. No significant difference was observed among the three groups of subjects for levels of antibodies against two non-intestinal bacteria and four of the intestinal bacteria. Patients with hepatosplenic schistosomiasis had titres of antibodies against one strain of Pseudomonas aeruginosa and one strain of Escherichia coli lower than those observed in other groups of subjects. Despite the partial obliteration of the hepatic blood outflow and the elevated portal pressure, hepatic clearance of the portal blood is efficient in chronic human schistosomiasis, and unlike alcoholic liver cirrhosis, avoids excessive stimulation of the immune system by a gut-derived antigens.

Immunochemical studies on the O-antigens of Proteus mirabilis O23 and Proteus vulgaris O23.

Analysis by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy demonstrated that the O-specific polysaccharides of Proteus mirabilis PrK 42/57 and P. vulgaris PrK 43/57 are structurally similar to that of P. vulgaris PrK 44/57 and different from the polysaccharide of P. mirabilis PrK 41/57 studied earlier. The lipopolysaccharides of these strains were tested using enzyme immunosorbent assay, passive hemolysis and Western blot with O-antisera against P. mirabilis 42/57 and P. vulgaris 43/57 and 44/57, as well as with cross-absorbed O-antisera. The chemical and serological data revealed the basis for combining the four strains into Proteus serogroup O23 and division of this serogroup to three subgroups, one for P. vulgaris 43/57 and 44/57 and two others for P. mirabilis 41/57 and 42/57.

Studies on nonspecific protection induced with OMP of Shigella flexneri and other genera of Enterobacteriaceae.

Outer membrane proteins (OMP) isolated from Shigella flexneri, Escherichia coli, Proteus vulgaris and Salmonella typhimurium were tested for their protective activity. Each OMP preparate given to mice intraperitoneally in a single injection (5 micrograms/per mouse) protected the animals not only in homologous but also in varying intensity in heterologous systems. Evidence was obtained that this nonspecific protection is cell mediated.

Immunogenic and protective properties of outer membrane proteins of Hafnia alvei.

Outer membrane proteins (OMP) extracted from antigenically distinct or related strains of Hafnia alvei containing defined composition of major proteins proved to be immunogenic. Intraperitoneal immunization of mice with a single dose of such preparations protected the animals against homologous and heterologous Hafnia strains. The OMP preparations were also found to induce protection with varying intensity against Escherichia, Proteus, Shigella and Salmonella.