Investigations on the efficacy of monovalent Pseudomonas aeruginosa vaccine for oral administration in Pseudomonas aeruginosa experimental infection

Therapeutic efficacy of Pseudomonas aeruginosa vaccine for oral use (10(10) killed germs/ml), prepared from strain 4922, belonging to serotype XV, by Meitert-Meitert scheme, on 4 experimental models in mice (pneumonia, infected burn, septicaemia and urinary tract infection) was studied in comparison with monovalent Ps. aeruginosa vaccine serotype XV (10(9) killed germs/ml) for subcutaneous use and also with associated administration of the two vaccine variants. Mice immunization by using vaccine for oral use was performed by 0.5 ml vaccine per day, for 10 days and vaccine for subcutaneous use was administrated in a volume of 0.5 ml x 2, at 3 days interval. Mice immunization by using the two vaccine types, in association was concomitantly performed and in the same quantity as for separate immunization. In experimental pneumonia, Ps. aeruginosa vaccine for oral use protected mice in 35% of cases, those with infected burns were protected in 33.3% of cases, those with septicemia--in 96.6% of cases and those with urinary tract infection in 50% of cases. As compared to Ps. aeruginosa vaccine for subcutaneous use, the results obtained by vaccine for oral use are less favourable but associated administration of both vaccine variants led to superior results. Thus, in experimental pneumonia, it was obtained a surviving rate of 65% for animals immunized with both vaccine types, in comparison with 50% for animals immunized with vaccine for subcutaneous use only, and in Ps. aeruginosa infected burn, it was obtained a recovering rate of 79.1% for the animals immunized by using both vaccines, in comparison with 70.8% surviving for animals immunized with vaccine for subcutaneous use. In experimental septicaemia and urinary tract infection, combined use of both vaccine variants determined animals surviving and recovering in percents similar to those obtained by separate administration of vaccine for subcutaneous use (in septicemia--100% protection; in urinary tract infection--75% protection).     

Production and experimental testing of the polyvalency of corpuscular vaccine for the prevention of Pseudomonas aeruginosa infections II. Experimental testing of the immunogenicity of polyvalent corpuscular Pseudomonas aeruginosa vaccine

Newly developed P. aeruginosa vaccine has been shown to be safe and apyrogenic for experimental animals. Immunization with the vaccine in a single injection of 0.5 ml has been found to ensure the protection of 80--98% of mice from lethal infection caused by virulent vaccine strains, with the exception of P. aeruginosa strain No. 1311, for 9 weeks. Immunity to P. aeruginosa strain No. 1311 develops only by day 56 after vaccination. No sharp correlation between the specific agglutinin level and the degree of protective effect induced by the immunization of animals with the polyvalent vaccine has been established. The vaccine has been shown to possess high immunogenicity in respect to clinical P. aeruginosa strains belonging to different serotypes (homo- and heterological vaccine strains).     

Protective action of a vaccine made from Salmonella minnesota R 595 in the intranasal infection of mice with P. aeruginosa

The comparative study of heated corpuscular vaccines prepared from S. minnesota mutant R 595, chemotype Re, from S. minnesota strain SF 1111 with defective lipopolysaccharide and from P. aeruginosa strain PA 103 has been carried out. The vaccine prepared from the chemotype Re mutant, in contrast to the vaccine prepared from S. minnesota strain SF 1111, has been found to induce the development of active immunity (and the corresponding antiserum, passive immunity) to P. aeruginosa introduced intranasally into mice, as well as to stimulate the elimination of the cells of P. aeruginosa infective strain from the lungs of the mice. The potency of the vaccine prepared from the chemotype Re mutant has been found to be significantly no different from that of the vaccine prepared from P. aeruginosa strain PA 103.     

Effectiveness of a polyvalent corpuscular Pseudomonas aeruginosa vaccine, antibiotics and their combinations in experimental chronic Pseudomonas aeruginosa infection

The data on the development of the experimental model of P. aeruginosa chronic infection in mice, produced by their intraperitoneal inoculation with the infective agent, and on the study of the properties of this model are presented. The model has been used in the experimental study of the preventive action of P. aeruginosa polyvalent corpuscular vaccine. The comparative study, carried out with the use of the proposed model, has been made with a view to evaluating the effectiveness of different methods for the treatment of P. aeruginosa chronic septic infection by means of antibiotics (polymixin B and tobramycin), P. aeruginosa polyvalent corpuscular vaccine and their combination. The combined use of this vaccine with antibiotics (polymixin B or tobramycin) has proved to give the most pronounced curative effect with respect to P. aeruginosa chronic infection.     

Production and study of the properties of a polyvalent corpuscular Pseudomonas aeruginosa vaccine. IV. The effect of immunization with Pseudomonas aeruginosa vaccine on the immune status of volunteer donors

The influence of immunization with P. aeruginosa vaccine on the immune status of volunteer donors has been studied. Immunization with P. aeruginosa vaccine in doses of 0.5-0.5-1.0 ml at intervals of 7 days has been found to lead to the 13-fold increase of the titer of specific antibodies, lasting for 3-4 months, which ensures the possibility of obtaining anti-P. aeruginosa hyperimmune plasma with standard titers. The injection of P. aeruginosa vaccine to donors leads to the activation of humoral immunity simultaneously with the increase of the absolute and relative number of rosette-forming B-lymphocytes without essential changes in the amount of rosette-forming T-lymphocytes.     

Chimeric animal and plant viruses expressing epitopes of outer membrane protein F as a combined vaccine against Pseudomonas aeruginosa lung infection

Outer membrane protein F of Pseudomonas aeruginosa has vaccine efficacy against infection by P. aeruginosa as demonstrated in a variety of animal models. Through the use of synthetic peptides, three surface-exposed epitopes have been identified. These are called peptides 9 (aa 261-274 in the mature F protein, TDAYNQKLSERRAN), 10 (aa 305-318, NATAEGRAINRRVE), and 18 (aa 282-295, NEYGVEGGRVNAVG). Both the peptide 9 and 10 epitopes are protective when administered as a vaccine. In order to develop a vaccine that is suitable for use in humans, including infants with cystic fibrosis, the use of viral vector systems to present the protective epitopes has been investigated. An 11-amino acid portion of epitope 10 (AEGRAINRRVE) was successfully inserted into the antigenic B site of the hemagglutinin on the surface of influenza virus. This chimeric influenza virus protects against challenge with P. aeruginosa in the mouse model of chronic pulmonary infection. Attempts to derive a chimeric influenza virus carrying epitope 9 have been unsuccessful. A chimeric plant virus, cowpea mosaic virus (CPMV), with epitopes 18 and 10 expressed in tandem on the large coat protein subunit (CPMV-PAE5) was found to elicit antibodies that reacted exclusively with the 10 epitope and not with epitope 18. Use of this chimeric virus as a vaccine afforded protection against challenge with P. aeruginosa in the mouse model of chronic pulmonary infection. Chimeric CPMVs with a single peptide containing epitopes 9 and 18 expressed on either of the coat proteins are in the process of being evaluated. Epitope 9 was successfully expressed on the coat protein of tobacco mosaic virus (TMV), and this chimeric virus is protective when used as a vaccine in the mouse model of chronic pulmonary infection. However, initial attempts to express epitope 10 on the coat protein of TMV have been unsuccessful. Efforts are continuing to construct chimeric viruses that express both the 9 and 10 epitopes in the same virus vector system. Ideally, the use of a vaccine containing two epitopes of protein F is desirable in order to greatly reduce the likelihood of selecting a variant of P. aeruginosa that escapes protective antibodies in immunized humans via a mutation in a single epitope within protein F. When the chimeric influenza virus containing epitope 10 and the chimeric TMV containing epitope 9 were given together as a combined vaccine, the immunized mice produced antibodies directed toward both epitopes 9 and 10. The combined vaccine afforded protection against challenge with P. aeruginosa in the chronic pulmonary infection model at approximately the same level of efficacy as provided by the individual chimeric virus vaccines. These results prove in principle that a combined chimeric viral vaccine presenting both epitopes 9 and 10 of protein F has vaccine potential warranting continued development into a vaccine for use in humans.     

Cell-free Pseudomonas vaccine: its immunochemical characteristics and immunogenicity

Two variants of cell-free protein vaccine have been prepared from the mixture of 4 P. aeruginosa strains, serovars 02, 06, 07 and 011, and from a single P. aeruginosa strain, serovar 02. The preparation contains proteins with molecular weight ranging from 20,000 to 100,000 and the admixture of lipopolysaccharide in negligible amounts (not exceeding 0.08% of dry weight). The vaccine produces no signs of toxicosis in laboratory animals. The vaccine effectively protects mice challenged with P. aeruginosa of different O-serotypes and stimulates the formation of specific protective antibodies in rabbits.     

Safety and sensitizing properties of a polyvalent corpuscular Pseudomonas aeruginosa vaccine and its effect on hematological indices

The acute and chronic toxicity, influence on hematological characteristics and sensitizing properties of P. aeruginosa polyvalent corpuscular vaccine have been studied in experiments on 3 species of animals. The acute experiment has shown that the LD50 of the preparation contains not less than 7800 million cells, which is almost 160 times higher than the recommended immunizing dose (500 million cells). The safety of the preparation is confirmed by the data obtained in the histological and histochemical investigations of the tissues and organs of animals subjected to multiple immunizations with the vaccine. These investigations have revealed no pathological changes in the animals. During the study of the chronic toxicity of the preparation the hematological characteristics of the animals have been found to remain within normal limits. The vaccine has been shown to possess low sensitizing activity, which is manifested by the absence of severe reactions to allergic skin tests with different bacterial allergens (specific allergens obtained from P. aeruginosa and allergens obtained from other bacterial species), made on completion of the course of immunization with the vaccine.     

Synthetic peptide vaccine and antibody therapeutic development: prevention and treatment of Pseudomonas aeruginosa

Pseudomonas aeruginosa and Pseudomonas maltophilia account for 80% of opportunistic infections by pseudomonads. Pseudomonas aeruginosa is an opportunistic pathogen that causes urinary tract infections, respiratory system infections, dermatitis, soft tissue infections, bacteremia, and a variety of systemic infections, particularly in patients with severe burns, and in cancer and AIDS patients who are immunosuppressed. Pseudomonas aeruginosa is notable for its resistance to antibiotics, and is therefore a particularly dangerous pathogen. Only a few antibiotics are effective against Pseudomonas, including fluoroquinolones, gentamicin, and imipenem, and even these antibiotics are not effective against all strains. The difficulty treating Pseudomonas infections with antibiotics is most dramatically illustrated in cystic fibrosis patients, virtually all of whom eventually become infected with a strain that is so resistant that it cannot be treated. Since antibiotic therapy has proved so ineffective as a treatment, we embarked on a research program to investigate the development of a synthetic peptide consensus sequence vaccine for this pathogen. In this review article we will describe our work over the last 15 years to develop a synthetic peptide consensus sequence anti-adhesin vaccine and a related therapeutic monoclonal antibody (cross-reactive to multiple strains) to be used in the prevention and treatment of P. aeruginosa infections. Further, we describe the identification and isolation of a small peptide structural element found in P. aeruginosa strain K (PAK) bacterial pili, which has been proven to function as a host epithelial cell-surface receptor binding domain. Heterologous peptides are found in the pili of all strains of P. aeruginosa that have been sequenced to date. Several of these peptide sequences have been used in the development of an consensus sequence anti-adhesin vaccine targeted at the prevention of host cell attachment and further for the generation of a monoclonal antibody capable of prevention and treatment of existing infections.     

Protective action of a corpuscular polyvalent Pseudomonas aeruginosa vaccine against representative enterobacteria

Animal experiments have demonstrated that P. aeruginosa vaccine is capable of protecting animals from experimental P. aeruginosa infection, as well as rendering a protective effect with respect to some representatives of the family Enterobacteriaceae. The comparative study of the antigenic spectra of the vaccine strains and some representatives of Enterobacteriaceae (Enterobacter, Serratia, Citrobacter and Klebsiella) has revealed no direct relationship between the degree of this protective effect and the presence of common antigenic determinants in them.     

Clinical study to assess the immunogenicity and safety of a recombinant Pseudomonas aeruginosa OprF-OprI vaccine in burn patients

In a recent clinical trial we evaluated the safety and immunogenicity of a recombinant OprF-OprI vaccine consisting of the mature outer membrane protein I (OprI) and amino acids 190-342 of OprF of Pseudomonas aeruginosa in burn patients and compared the elicited antibodies with antibodies against tetanus as response to a simultaneous immunization given on the day of admission. Safety and immunogenicity of the vaccine had been tested before in healthy human volunteers as published in 1999. In this first clinical trial we immunized eight burn patients suffering from second or third degree burns involving between 35% and 55% of the body surface three times with 100 microg of the OprF-OprI vaccine. The vaccine was found to be very well tolerated. The patients did not show any serious side effects - and in particular no activation of the mediator cascade was observed. None of the subjects showed systemic P. aeruginosa infections during or after the treatment of their burns. The serological tests (ELISA) for detection of antibodies against P. aeruginosa and tetanus toxoid showed seroconversion for seven patients after inoculation. The data indicate that OprF-OprI can be a useful vaccine in the therapeutic management of burn injuries.     

Experimental immunological effectiveness and safety of pyoimmunogen vaccine against Pseudomonas aeruginosa infection

Pyoimmunogen, a polycomponent vaccine against P. aeruginosa infection, has been obtained in laboratory and semi-industrial conditions. The microbial biomass obtained from the strains belonging to O-serotypes (immunotypes) most frequently occurring in clinical practice has been used for producing protective antigens. The preparations have been found to contain proteins (peptides) and carbohydrates in the ratio 6 : 1 to 8 : 1, as well as traces of 2-keto-3-desoxyoctanate, which is indicative of the low content of endotoxin. The immunogenicity of the preparations has been studied experimentally by the active immunization of mice. In these experiments the animals vaccinated in a single injection were found to be protected from challenge with both homologous and heterologous P. aeruginosa strains. The high level of protection from infection caused by toxigenic strain PA-103 was registered. The preparations have low toxicity: LD50 for mice exceeds 2 mg (in protein content): after the multiple administration (7-10 times) of the preparation to mice and rats the weight of the experimental animals was not significantly different from the weight of the control animals.     

Vaccines against Pseudomonas aeruginosa results and perspectives of investigations (survey)

At the present time, there are many preparations for active immunization against P. aeruginosa infection (pseudomonas infection), but none of the proposed preparations has so far been widely used in medical practice. Development of P. aeruginosa vaccine (PV) should obviously be based on findings concerning the pathogenesis of infection, the mechanisms of immunogenesis and the factors of virulence of the causative agent. On the basis of results of their studies the authors believe that PV should include a non-toxic low-molecular component (or components) of the extracellular slime and water-soluble protein antigens of the cell wall, isolated from one or three selected strains of P. aeruginosa. Adoption of these components onto aluminium hydroxide can obviously increase the efficiency of PV.     

Results of using polyvalent Pseudomonas aeruginosa vaccine in children with burns by various medical centers

Polyvalent Pseudomonas aeruginosa vaccine, prepared at the Institute of Hematology from 10 hospital strains isolated from burn wounds, was administered to 32 children with extensive and deep burns. The vaccine was well tolerated. The vaccine produced a high degree of the immunity against Pseudomonas aeruginosa infection. Agglutinin serum titre increased significantly. Vaccination either prevented or inhibited the infection of burn wounds with Pseudomonas aeruginosa in all immunized children. The symptoms of Pseudomonas aeruginosa infection usually disappeared following one or two vaccinations. Bacteriemia caused by P. aeruginosa was not observed in 31 out of 32 children. In the remaining child transient bacteriemia was noted. No septicemia caused by P. aeruginosa was seen. Due to the high efficiency of the polyvalent P. aeruginosa vaccine all burned children with burns exceeding 10% of the total body surface should by vaccinated to prevent the life-threatening infections with Pseudomonas aeruginosa.     

Characterization by pyocine typing and serotyping of oral and sputum strains of Pseudomonas aeruginosa isolated from cystic fibrosis patients

Oral and sputum isolates of Pseudomonas aeruginosa in patients with cystic fibrosis were investigated. Of the 17 patients studied, 12 patients (71%) yielded both mucoid and nonmucoid variants of Pseudomonas aeruginosa from sputum and (or) various oral ecological sites, such as buccal mucosa, tongue dorsum, dental plaques, and saliva. A total of 51 strains of mucoid and nonmucoid Pseudomonas aeruginosa were isolated from these patients and were phenotypically characterized by both pyocine typing and serotyping. Five patients (42%) were colonized or infected by a single strain of Pseudomonas aeruginosa, whereas 7 patients (58%) were cocolonized or coinfected by two or more phenotypically different strains of Pseudomonas aeruginosa. To understand the mechanisms involved in Pseudomonas aeruginosa colonization, it may be necessary to identify multiple isolates of Pseudomonas aeruginosa not only from the sputum but also from the various oral ecological sites and to further explore the role of the oral cavity in this colonization.     

Experimentally determined safety and immunological activity of vaccine based on antigens isolated from Pseudomonas aeruginosa in medium K-4

The safety and immunological activity of P. aeruginosa vaccine were experimentally evaluated. The vaccine was prepared on the basis of the antigens of P. aeruginosa extracellular slime which was accumulated in medium K-4, obtained with the use of original technology. The immunization of animals with P. aeruginosa vaccine induced the synthesis of antibodies. The introduction of the vaccine in 2 or 3 injections resulted in a high level of antibody formation, differing with the use of various strains. Hyperimmune sera, obtained by the multiple immunization of rabbits with P. aeruginosa vaccine, ensured high protection of mice from P. aeruginosa infection. The vaccine proved to be safe when evaluated in experiments of acute and chronic toxicity, made on laboratory animals.     

Enhancement of the protective efficacy of an oprF DNA vaccine against Pseudomonas aeruginosa

The outer membrane protein F gene (oprF) of Pseudomonas aeruginosa was recently shown by us to protect mice from P. aeruginosa chronic pulmonary infection when used as a DNA vaccine administered by three biolistic (gene gun) intradermal inoculations given at 2-week intervals. In the present study, we used two different strategies to improve the protective efficacy of the DNA vaccine. In the first strategy, mice were primed with two biolistic intradermal inoculations with the oprF vaccine and then were given a final intramuscular booster immunization containing either a synthetic peptide-keyhole limpet hemocyanin (KLH) conjugate or a chimeric influenza virus. Both the synthetic peptide conjugate and the chimeric virus contained peptide 10, a previously identified immunoprotective epitope of protein F. The second strategy involved the addition of a second outer membrane protein to the vaccine. DNA encoding a fusion protein comprised of the C-terminal half of protein F fused to OprI was administered by three biolistic intradermal inoculations. Challenge with P. aeruginosa in a chronic pulmonary infection model demonstrated that boosting with the chimeric virus (but not with peptide-KLH) or adding oprI to the DNA vaccine significantly enhanced protection as compared to that afforded by the oprF vaccine given alone. Thus, both strategies appear to augment the protection afforded by an oprF-only DNA vaccine.     

Spatio-temporal Use of Oral Rabies Vaccines in Fox Rabies Elimination Programmes in Europe

In Europe, the elimination of wildlife rabies using oral rabies vaccination [ORV] of foxes for more than 30 years has been a success story. Since a comprehensive review on the scope of the different oral rabies vaccine baits distributed across Europe has not been available yet, we evaluated the use of different vaccine baits over the entire period of ORV [1978–2014]. Our findings provide valuable insights into the complexity of ORV programs in terms of vaccine related issues. More than 10 oral vaccines against rabies were used over the past four decades. Depending on many factors, the extent to which oral rabies virus vaccines were used varied considerably resulting in huge differences in the number of vaccine doses disseminated in ORV campaigns as well as in large spatial and temporal overlaps. Although vaccine virus strains derived from the SAD rabies virus isolate were the most widely used, the success of ORV campaigns in Europe cannot be assigned to a single oral rabies virus vaccine alone. Rather, the successful elimination of fox rabies is the result of an interaction of different key components of ORV campaigns, i.e. vaccine strain, vaccine bait and strategy of distribution.     

BCG Moreau Rio de Janeiro: an oral vaccine against tuberculosis--review

The vaccine Bacillus of Calmette Guérin (BCG) was originally developed in France as an oral vaccine against tuberculosis. The oral use of this vaccine was replaced by the parenteral route in almost all countries after the Lubeck disaster. In contrast, Brazil retained the oral delivery of the vaccine until the mid-seventies when it was replaced by the intradermal route. This change in route of delivery was mainly secondary to pressure by medical practitioners based on the poor responses of oral immunized subjects to purified protein derivative (PPD) skin tests. Even after the change of route of delivery, Ataulpho de Paiva Foundation continued making the oral vaccine. Currently, BCG Moreau has been described as one of the most immunogenic and with fewer side effects than other BCGs. The genomics, proteomics and vaccine trials for oral BCG Moreau Rio de Janeiro are currently under investigation. In this review, we intend to describe the history of BCG Moreau Rio de Janeiro in Brazil.     

Interaction of a bacterially expressed peptide from the receptor binding domain of Pseudomonas aeruginosa pili strain PAK with a cross-reactive antibody: conformation of the bound peptide

The C-terminal receptor binding region of Pseudomonas aeruginosa pilin protein strain PAK (residues 128-144) has been the target for the design of a vaccine effective against P. aeruginosa infections. We have recently cloned and expressed a (15)N-labeled PAK pilin peptide spanning residues 128-144 of the PAK pilin protein. The peptide exists as a major (trans) and minor (cis) species in solution, arising from isomerization around a central Ile(138)-Pro(139) peptide bond. The trans isomer adopts two well-defined turns in solution, a type I beta-turn spanning Asp(134)-Glu-Gln-Phe(137) and a type II beta-turn spanning Pro(139)-Lys-Gly-Cys(142). The cis isomer adopts only one well-defined type II beta-turn spanning Pro(139)-Lys-Gly-Cys(142) but displays evidence of a less ordered turn spanning Asp(132)-Gln-Asp-Glu(135). These turns have been implicated in cross-reactive antibody recognition. (15)N-edited NMR spectroscopy was used to study the binding of the (15)N-labeled PAK pilin peptide to an Fab fragment of a cross-reactive monoclonal antibody, PAK-13, raised against the intact PAK pilus. The results of these studies are as follows: the trans and cis isomers bind with similar affinity to the Fab, despite their different topologies; both isomers maintain the conformational integrity of their beta-turns when bound; binding leads to the preferential stabilization of the first turn over the second turn in each isomer; and binding leads to the perturbation of resonances within regions of the trans and cis backbone that undergo microsecond to millisecond motions. These slow motions may play a role in induced fit binding of the first turn to Fab PAK-13, which would allow the same antibody combining site to accommodate either trans or cis topology. More importantly for vaccine design, these motions may also play a role in the development of a broad-spectrum vaccine capable of generating an antibody therapeutic effective against the multiple strains of P. aeruginosa.