Protective Activity and Safety of Experimental Acellular Pertussis Vaccines Based on Antigenic Complexes Isolated from Biofilm and Planktonic Cultures of Bordetella pertussis.

Continued circulation of the whooping cough pathogen, even in countries with high vaccine coverage, can be related to persistence of Bordetella pertussis biofilms in the respiratory tract. The films differ from planktonic cells by increased resistance to the host immune system and antibacterial drugs. The available acellular pertussis vaccines (aPV) containing antigens isolated from planktonic cultures of B. pertussis protect from severe forms of whooping cough, but do not effectively influence circulation of virulent strains in the subclinical forms of the disease and asymptomatic carriage. It is promising to create new generation aPV based on antigens isolated from biofilm cultures of B. pertussis capable of more effectively controlling the entire infectious cycle of whooping cough, including colonization, persistence, and transmission of the pathogen. From antigenic complexes isolated from the culture medium of biofilm and planktonic cultures of the strain B. pertussis No. 317 (serotype 1.2.3), experimental aPV were made: aPV-B and aPV-P, respectively. In intracerebral infection of mice with a virulent strain of B. pertussis, aPV-B demonstrated 2.5-fold higher protective activity than aPV-P and also more effectively reduced colonization of the lungs by B. pertussis cells in mice after intranasal infection with a virulent strain. Both vaccine preparations were safe and did not cause death in mice after administration of histamine.

[PROFILES OF CYTOKINES IN MICE DURING IMMUNIZATION WITH ADTP- VACCINE WITH ACELLULAR PERTUSSIS COMPONENT].

AIM: Study cytokine status in mice immunized with vaccines containing acellular pertussis component. MATERIALS AND METHODS: Vaccines developed in Mechnikov RIVS - acellular pertussis vaccine (aPV) and adsorbed pertussis-diphtheria-tetanus vaccine (aDTaP), containing a complex of protective antigens of pertussis microbe - were used in the study. F1 (CBAxC57B16) line mice weighing 12 - 14 g were immunized intraperitoneally 3 times at an interval of 7 days with aPV and aDTaP at human immunization dose (0.5 ml), containing 25 µg of pertussis component. Intact mice were used as a control group. Levels of IFN-,γ, IL-2, IL-4, IL-5, IL-12 cytokines were de- termined after each immunization in enzyme immunoassay using commercial test-systems from Cusabio (China). RESULTS: An increase of levels of IFN-γ, IL-2, IL-5, IL-12 and lack of stimulation of production of IL-4 was established in dynamics of immune response after administration of aPV and aDTaP vaccines. CONCLUSION: The data obtained indicate that immunization of mice with aPV and aDTaP vaccines resulted in activation of production of cytokines characteristic for im- mune response during pertussis infection and immunization with whole-cellular aDTP-vaccines.

[Immunobiological properties of Bordetella pertussis lipopolysaccharide in the acellular pertussis vaccine].

AIM: Study of Bordetella pertussis lipopolysaccharide (LPS) immunobiological properties in the acellular pertussis vaccine. MATERIALS AND METHODS: Experimental series of acellular pertussis vaccines (APV), lyophilized LPS were used. Antibody titers against LPS in mice sera were evaluated by using EIA with peroxidase conjugate of anti-species antibodies against mice IgG. LPS activity in B. pertussis antigen complex preparations was determined in quantitative chromogenic LAL-test by end point. APV protective activity was determined in mice test during intracerebral infection by B. pertussis strain No. 18323 virulent culture. APV safety was determined in the mice body weight change test. RESULTS: The presence of LPS in APV was shown in immune electrophoresis with purified B. pertussis LPS preparation as a control. Formalin treatment changes immunochemical properties of APV LPS that lead to the shift of precipitation bands with pertussis agglutinating sera from the start zone into cathode. The quantity of LPS in pertussis culture supernatants was on average 49050 +/- 6774 endotoxin units per ml (EU/ml). In APV preparations the quantity of LPS was on average 906 +/- 90 EU/ml, i.e. decreased by more than 50 times. An increase of antibody titers against B. pertussis LPS in mice sera after the APV immunization was shown in EIA, which gives evidence of its presence in immunogenic form in the complex preparations. The preclinical studies carried out show protective activity and specific safety of the experimental APV series. CONCLUSION: Formalin-neutralized APV preparation is a complex of protein antigens in association with LPS. Formalin treatment results in modification of LPS molecule that retains antigenic properties but is significantly less toxic.

[Immunogenicity and safety of vaccine preparations based on circulating Bordetella pertussis strains].

AIM: Study specific activity and safety ofvaccine preparations based on circulating B. pertussis strains with currently predominating allele variants of pertussis toxin (ptxA1) and pertactin (prn2) genes. MATERIALS AND METHODS: B. pertussis strains isolated from pertussis patients in Moscow in 2001-2010 were grown in dense and liquid media. The content of separate antigens in B. pertussis strains was determined by EIA. Immunogenicity and safety of the preparations was determined in F1(CBAxC57B16) line mice. RESULTS: All the studied circulating B. pertussis strains expressed pertussis toxin (PT), filamentous hemagglutinin (FHA) and agglutinogens corresponding to the serovar. Whole-cell and acellular pertussis vaccines were prepared based on the circulating strains, and a highly productive recently isolated toxigenic B.pertussis strain that could be used for production ofpertussis vaccines was selected as a result of studies ofimmunogenic, toxic and sensibilizing properties. CONCLUSION: Vaccine preparations based on a B. pertussis strain adapted to growth in liquid media with pertussis toxin and pertactin ptxAl1 - prn2 gene allele variation characteristic for contemporary population are specifically active and safe.

[Preclinical studies of an adsorbed diphtheria-tetanus-pertussis vaccine (ADTP-vaccine) with acellular pertussis component].

AIM: Evaluate standardness of antigenic composition of pertussis component, completeness of sorption of pertussis, diphtheria and tetanus components, specific activity and safety of experimental series ofADTP-vaccine with acellular pertussis component (ADTaP-vaccine). MATERIALS AND METHODS: The content of separate antigens (pertussis toxin, filamentous hemagglutinin and agglutinogens 1, 2, 3) in samples of acellular pertussis component of ADTaP-vaccine and completeness of sorption of pertussis component of ADTaP-vaccine were evaluated by using enzyme immunoassay. Completeness of sorption of diphtheria and tetanus components were determined in flocculation reaction and antitoxin-binding reactions, respectively. Protective activity ofADTaP-vaccine was studied in model ofmeningoencephalitis development in mice infected with Bordetella pertussis (strain 18323) neurotropic virulent culture, protective activity oftetanus component - by survival of mice after administration of tetanus toxin, protective activity of diphtheria component - by survival of guinea pigs after administration of diphtheria toxin. Safety of preparations was evaluated in tests of acute and chronic toxicity with carrying out pathomorphologic studies including immature animals. RESULTS: All the studied experimental series ofADTaP-vaccine were standard by content of separate antigens of pertussis microbe. All the ADTaP-vaccine components were completely sorbed on aluminium hydroxide gel. By protective activity ADTaP preparations satisfied the WHO requirements. The preparations were non-toxic in acute and chronic toxicity and did not induce pathomorphologic changes including immature animals. CONCLUSION: Experimental samples of ADTaP-vaccine by specific activity and safety satisfied WHO requirements.

[Medical and biological safety assessment of genetically modified soybean event MON 89788. Report 2. Genotoxicologic, immunologic and allergologic examinations].

There are presented the results of genotoxicologic, immunologic and allergologic examinations which were conducted within the framework of integrated medical and biological assessment of genetically modified second generation soybean event MON 89788. Analysis of damages of DNA and structural chromosome aberrations, assessment of the allergenic potential and immunoreactive properties has not confirmed any genotoxic, allergenic and immunotoxic effect of soybean event MON 89788.

[Dynamics of changes in pathogenic characteristics of Bordetella pertussis strains].

AIM: To study pathogenic characteristics of B. pertussis strains isolated from patients during different periods of pertussis infection epidemic process. MATERIALS AND METHODS: Strains of B. pertussis isolated in Moscow during 1967 - 1971, 1980 - 1985, and 2001 - 2005 were studied. Nutrient media: Bordet-Gengou blood agar, casein-charcoal agar. ANIMALS: mice - F1 hybrids (CBA x C57BL6). Pathogenic characteristics of strains were studied by assessment of virulence (LD50), leukocytosis-stimulating (LS units) and histamine-sensitizing (HSD50) activities of cultures. Genotyping was performed using standard equipment and reagents for DNA isolation, amplification, sequencing and detection of results. RESULTS: On the sample of 164 strains, pathogenic and genotypic characteristics of B. pertussis populations circulated during 1967 - 1971, 1980 - 1985, and 2001 - 2005. Majority of B. pertussis strains isolated in 1967 - 1971 and strains circulated during current phase of epidemic process were virulent (80.75% and 81.8% respectively) and had significant leukocytosis-stimulating and histamine-sensitizing activity, whereas strains isolated from patients with pertussis in 1980 - 1985 characterized by lower virulence and toxicity. Genotyping showed strains carrying "non-vaccine" allele ptxA1, which emerged in the middle of 1970s, totally displaced strains with "vaccine" alleles ptxA2 and ptxA4. CONCLUSION: Adaptive changes of B. pertussis driven by increased vaccination coverage involve both ptxA gene and pathogenic characteristics of infectious agent in the range of genotypically homogenous population with domination of strains, which have high levels of virulence and toxicity.

[Antigenic composition and serologic characteristics of domestic acellular pertussis vaccine].

AIM: To assess antigenic composition consistency and serological characteristics of domestic acellular pertussis vaccine. MATERIALS AND METHODS: Amount of pertussis toxin, filamentous hemagglutinin, agglutinogens types 1, 2, and 3 in experimental batches of vaccine was measured by enzyme immunoassay. Levels of antibodies to aforementioned antigens as well as to lipopolysaccbaride in serum samples obtained from patients with pertussis and healthy vaccinated children were measured by the same method. The amount of lypopolysaccharide was determined by LAL test. RESULTS: Studied batches of vaccine were standard on amount of all protein antigens as well as lipopolysaccharide. Spectrum of antibodies to vaccine components in serum samples from patients with pertussis and healthy vaccinated children included antibodies to individual antigens: pertussis toxin, filamentous hemagglutinin, lipopolysaccharide, agglutinogens types 1, 2, and 3. CONCLUSION: Developed technology for manufacturing acellular pertussis vaccine allows to consistently produce preparations with standard amount of all components. Vaccine components interact with antibodies to wide spectrum of B. pertussis antigens.

[Medical and biological safety assessment of genetically modified maize event MIR604].

There are presented the results of genotoxicologic, immunologic and allergologic examinations which were conducted within the framework of integrated medical and biological assessment of genetically modified rootworm Diabrotica spp.-protected maize event MIR604. Analysis of damages of DNA and structural chromosome aberrations, assessment of the allergenic potential and immunoreactive properties has not confirmed any genotoxic, allergenic and immunotoxic effect of maize event MIR604.

[Acellular pertussis vaccine].

Protective, immunogenic, toxic, and sensitizing properties of acellular pertussis vaccine (aPV) developed according to original technology were studied, aPV had marked protective activity which lasted more than 2 years. Sera of mice immunized by aPV also possess protective properties, and they were more prominent than in sera of mice immunized by pertussis bacteria suspension (PS). Immune sera to aPV neutralized cytopathogenic effect of pertussis toxin (PT) on ovarian Chinese hamster cells in 1:250 dilution, whereas neutralizing activity of sera to PS was very low. Level of antibodies to PT was higher in rabbits immunized, according to schedules and dosage recommended for children, by aPV than by PS. High immunogenicity of aPV was proved also by levels of IgG to PT in sera of mice immunized three times by aPV in human dosage. During experiments on mice and guinea pigs aPV had mild toxicity, did not induce autoimmune process, did not have anaphylactogenic properties compared with bacterial suspension characterized by high anaphylactogenic activity. Histamine-sensitizing abilityof aPVwas 40 times lower than that of PS. Assessment of pyrogenic properties of aPV and PS performed on rabbits showed that aPV was 1,000 times less pyrogenic than PS. Obtained results demonstrate high protective and immunogenic properties of domestic acellular pertussis vaccine and its low toxic and sensitizing characteristics.

[Medical and biological safety assessment of genetically modified maize event MON 88017. Report 2. Genotoxicologic, immunologic and allergologic examinations].

There are presented the results of genotoxicologic, immunologic and allergologic examinations which were conducted within the framework of integrated medical and biological assessment of genetically modified rootworm Diabrotica spp.--protected and glyphosate tolerant maize event MON 88017. Analysis of damages of DNA and structural chromosome aberrations, assessment of the allergenic potential and immunoreactive properties has not confirmed any genotoxic, allergenic and immunotoxic effect of maize event MON 88017.

[Modern strains of Bordetella pertussis: immunobiological properties and vaccine improvement].

Strains of B. pertussis isolated from patients in Moscow in 2001-2005 as well as strains included in locally produced diphtheria-tetanus-whole cell pertussis (DTP) vaccine were studied. Nucleotide sequences in genes of pertactin and S1-subunit of pertussis toxin of isolated strains, their immunobiological properties and opportunity to use for producing of the acellular pertussis vaccine were determined. Genes of pertactin and S1-subunit of pertussis toxin in the isolated wild strains differed from the same genes in strains included in the local DTP vaccine. Majority of the isolated strains belonged to serotype 1.0.3 and were markedly virulent.

[Protective activity of adsorbed D(a)PT vaccine with the acellular pertussis component and polyoxydonium].

The introduction of the immunomodulator polyoxidonium in an amount of 0.5 Mg/ml into adsorbed D(a)PT vaccine with the acellular pertussis component leads to the preservation of the protective activity of the pertusis component, diphtheria and tetanus toxoids, as well to the 4-time decrease of the content of adsorbent (aluminium hydroxide) from 2 to 0.5 mg/ml.

[Comparative study of the immunologic effectiveness of the oral and subcutaneous methods of administering pertussis vaccine]. / Sravnitel'noe izuchenie immunologicheskoi éffektivnosti peroral'nogo i podkozhnogo metodov vvedeniia kokliushnoi vaktsiny

The authors present the results of study of humoral immunity in rabbits after oral and subcutaneous immunization with pertussis vaccine. There was an increase in agglutinin titre and of the protective properties of the serum both after the oral administration of the vaccine according to two different schemes and after the subcutaneous immunization. However, rabbits immunized orally displayed a more prolonged (150-day) persistence of agglutinin titres, as well as of preventive and protective activity of the sera than rabbits immunized subcutaneoulsy.

[The effect of bacterial and synthetic peptidoglycans on the toxicity of a cell-free pertussis preparation]. / Vliianie bakterial'nykh i sinteticheskikh peptidoglikanov na toksichnost' beskletochnogo kokliushnogo preparata.

The influence of bacterial and synthetic peptidoglycans on the toxicity of acellular pertussis preparations (APP) has been studied in the mouse weight gain test and in the endotoxic shock development test on mice treated with Actinomycin D. The data obtained in these tests indicate that the immunomodulators (IM) under study are capable of changing (increasing or decreasing, depending on the dose) the toxic properties of APP. The antitoxic action of IM, established in this study, depends on the combination of the doses of IM and APP and the time elapsed from the time of immunization. The possibility of using these IM in a dose of 0.0001 microgram for reducing the LD50 of APP has been established. The use of IM belonging to the group of bacterial synthetic peptidoglycans for the development of acellular pertussis vaccines with reduced reactogenicity has been shown to hold much promise.

[Immunomodulation activity of new vaccines for pertussis prophylaxis--acellular pertussis vaccine and adsorbed DPT vaccine with acellular component]. / Otsenka immunomoduliruiushchei aktivnosti novykh preparatov dlia profilaktiki kokliusha--beskletochnoi kokliushnoi vaktsiny i AKDS-vaktsiny s beskletochnym kokliushnym komponentom.

The immunomodulating activity of acellular pertussis vaccine (APV) and adsorbed DPT vaccine with acellular pertussis component (DPTA vaccine) was studied. The study revealed that only large doses of APV, 10 immunizing doses (ID), suppressed humoral and cell-mediated response to sheep red blood cells (SRBC). 1 ID produced no influence on the formation of antibody producing cells, but increased the development of delayed hypersensitivity (DH) to SRBC. The modulation of cell-mediated immune response, induced by APV, returned to normal after the injection of purified staphylococcal toxoid, used as immunomodulator, in doses of 0.15 BU per mouse and 1.5 BU per mouse. DPTA vaccine containing 1 ID, as well as 10 ID, produced no immunomodulating effect. This was established by the evaluation of humoral response to SRBC in CBA mice and the study of the formation of DH to SRBC in BALB/c mice. As indicated by the total of the presented data, the inclusion of APV into DPTA vaccine enhanced the immunological safety of its pertussis component.

[Effect of blastolysin on the development of specific immunity to whooping cough]. / Vliianie blastolizina na razvitie spetsificheskogo immuniteta k kokliushu.

The influence of blastolysin, the cell-wall glycopeptide of Lactobacillus bulgaricus, on the main immunobiological properties of pertussis vaccine, its immunogenicity and toxicity, has been studied. The use of blastolysin, introduced as a stimulating agent in definite doses and following definite administration schedules, has been shown to permit achieving not only an increase in the immunogenicity of the corpuscular pertussis vaccine, but also a considerable decrease in its toxicity and histamine-sensitizing activity.

[Action of plant extracts on the natural immunity indices of animals]. / Izuchenie deistviia rastitel'nykh ékstraktov na pokazateli estestvennogo immuniteta zhivotnykh.

The influence of extracts from oak bark, St. John's-wort leaves and pine buds on natural immunity characteristics of mice has been studied. The injection of these extracts into mice has been found to enhance their resistance to infection with Staphylococcus aureus and Bordetella pertussis virulent cultures, to decrease the enzymatic activity of 5'-nucleotidase in the peritoneal exudate macrophages of mice and to increase the level of lysozyme in their blood. The action of these extracts has proved to depend on their dosage and the time of observation.

[The action of pertussis vaccines and GMDP on the change in the enzymatic activity of macrophages from peritoneal exudate]. / Izuchenie deistviia kokliushnykh vaktsin i GMDP na izmenenie fermentativnoi aktivnosti makrofagov peritoneal'nogo ékssudata.

The influence of whole-cell and acellular pertussis vaccines, introduced both alone and in combination with N-acetylglucosaminylmuramyl-2-alanine-D-isoglutamine (GMDP) on the activity of two enzymes of peritoneal exudate macrophages (5'-nucleotidase and Na+K(+)-adenosine triphosphatase) was studied. The study revealed that both pertussis vaccines exhibited immunomodulating properties, these properties being most pronounced in whole-cell pertussis vaccine. The use of GMDP in combination with pertussis vaccines led to changes in the enzymatic activity of peritoneal exudate macrophages, which was indicative of a decrease in the immunomodulating action of pertussis preparations.

[The use of pharmacological screening for characterizing the toxicity of pertussis vaccines]. / Ispol'zovanie farmakologicheskogo skrininga dlia kharakteristiki toksichnosti kokliushnykh vaktsin.

The influence of pertussis preparations, introduced by oral and parenteral routes, on the detoxifying function of the liver and the state of the nervous system of the animals was studied by methods used in pharmacology and toxicology. The use of these methods made it possible to find out side effects produced by corpuscular pertussis vaccine, introduced parenterally, on the detoxifying function of the liver and the state of the nervous system of the animals. The negative influence on the nervous system was more pronounced after the injection of the commercial adsorbed diphtheria-pertussis-tetanus vaccine used in this investigation than after the injection of pertussis monovaccine. The oral administration of corpuscular pertussis vaccine exerted no negative influence on the above-mentioned body functions of the animals.