Evaluation of postvaccinal pertussis immunity by using immunoenzyme analysis

The effectiveness of adsorbed DPT vaccine manufactured in the USSR, evaluated by its capacity of inducing the formation of the main classes of immunoglobulins and by the duration of immune response to the acellular complex of protective antigens (pertussis toxin and agglutinogen-2), was studied with the use of modified EIA. Out of 273 children immunized with adsorbed DPT vaccine in the course of this study, 87.2% had IgG-antibodies, 14.1% had IgA-antibodies and 3.2% of the children had IgM-antibodies. The level of immunity in children having received the full course of immunization with adsorbed DPT vaccine was significantly higher in comparison with children given only the primary course of immunization and nonimmunized children of the same age. Antipertussis immunity was found to decrease two years after the completion of the course of immunization with adsorbed DPT vaccine and in children over 5-6 years of age. Adsorbed DPT vaccine prevented the disease, but not infection. The level of postinfection immunity was higher than that of postvaccinal immunity.     

Prophylaxis of pertussis: development and use of acellular pertussis vaccine

Modern data substantiating the expediency of the use of acellular pertussis vaccine were analyzed. Serious postvaccinal complications caused by the action of the corpuscular pertussis component of adsorbed DPT vaccine served as the basis for the development of acellular pertussis vaccine (APV). During the period of 1990-1996 as many as 8 international field trials of the effectiveness of APV were carried out. The results of these trials and studies were evaluated in accordance with the unified programs and criteria. The vaccines under test differed by the composition of Bordetella pertussis purified antigens they contained, the methods of their purification and the detoxification of pertussis toxin. All tested APV, with the exception SKB-2, possessed pronounced prophylactic activity.     

Antigenic similarity of the pertussis component of adsorbed DTP vaccine to human erythrocytes

The similarity of the heterogeneous antigens, types A and B, of human red blood cells to the most of B. pertussis strains constituting the pertussis component of commercial batches of adsorbed DPT vaccine has been established. This property makes the vaccine strains different from B. pertussis isolated from pertussis patients. One of the reasons of the insufficient effectiveness of immunization against pertussis has been determined: the intensity of immune response depends on the antigenic heterogeneity of the pertussis component of the vaccine and the AB0 group factors in the blood of the vaccinees. For the first time the accumulation of immune alpha- and beta-isoagglutinins in the blood of persons immunized with absorbed DPT vaccine has been established. This accumulation shows the medium degree of direct correlation with the manifestations of the clinical reaction to the injection of the vaccine. The data obtained in this study indicate the necessity to revise the existing method of obtaining the pertussis component of adsorbed DPT vaccine on solid culture media with human red blood cells added and to develop the technique of the additional purification of this component from heterogeneous antigens.     

Comparative study of the immunoglobulins and specific antibodies in the blood of rabbits immunized with ADTP vaccine and ADT-anatoxin with normal and reduced antigen contents

Adsorbed DPT vaccine and adsorbed DT toxoids with normal and reduced antigen content were used for the immunization of rabbits. The levels of IgM and IgG and the dynamics of antibodies to diphtheria and tetanus toxins and to Bordetella pertussis in the blood sera of the animals were studied in the postvaccinal period (on days 15 and 34). This study revealed that the reduction of the antigen content of adsorbed DT toxoid to 5 Lf of diphtheria toxoid and 5 binding units of tetanus toxoid did not decrease the capacity of the preparation for increasing the levels of IgG and IgM, antibodies to diphtheria and tetanus toxins in the sera of the rabbits. The reduced content of these toxoids in adsorbed DPT vaccine did not affect its capacity for inducing the enhanced synthesis of IgG, antibodies to diphtheria and tetanus toxins, while the production of IgM and IgA remained unchanged. At the same time an increase in the titers of antibodies to B. pertussis in the animals was less pronounced than that observed after the injection of commercial adsorbed DPT vaccine. Additional investigations are necessary in order to establish the protective potency of the pertussis component in adsorbed DPT vaccine with the reduced content of toxoids and to find out the optimum antigenic composition for this preparation.     

Immunomodulation activity of new vaccines for pertussis prophylaxis--acellular pertussis vaccine and adsorbed DPT vaccine with acellular component

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.     

The formation of a test system for assessing the safety of different types of pertussis preparations: their cytotoxic action on mouse thymocytes in vitro

The test for the evaluation of the toxicity of different types of pertussis preparations as manifested by their in vitro influence on mouse thymic cells (T test) has been finally worked out. The use of the T test has made it possible to reveal the nonstandard character of the production lots of adsorbed diphtheria-pertussis-tetanus vaccines, both whole-cell vaccine and Japanese acellular vaccine. The degree of the in vitro damaging action of pertussis preparations on mouse thymic cells greatly depends on the residual content of Bordetella pertussis nontoxoidized toxin which, in contrast to B. pertussis lipopolysaccharide and filamentous hemagglutinin, produces pronounced cytotoxic action on mouse thymic cells.     

Evaluation of the stability of pertussis vaccine OCO-3 standard

The evaluation of the immunogenic activity and residual toxicity of the National Standard of pertussis vaccine (OCO-3) was carried out. As shown by observations lasting for a period of 25 years, the preparation possesses stable immunogenicity and its toxicity remained unchanged, which makes it possible to use OCO-3 for the routine control of the pertussis component of commercial lots of adsorbed DPT vaccine.     

DTaP vaccines from north american vaccine (NAVA): composition and critical parameters.

NAVA's acellular pertussis vaccine is based on highly purified pertussis toxin (PT) inactivated with H(2)O(2). PT was analysed using advanced biochemical methodology including mass spectroscopy (LC/MS), yielding mass and peptide mapping information on the subunits. Pertactin, adenylate cyclase, and Fim 1, 2 were below detection levels and only trace amounts of filamentous haemagglutinin (FHA) have been identified as a minor impurity. The vaccine does not induce anti-FHA antibodies during the course of a 3-dose primary immunization series in infants. B and T cell epitopes are preserved to a higher extent after H(2)O(2)detoxification when compared with chemical inactivation with formaldehyde, thus providing new information explaining why vaccines employing formaldehyde detoxified PT may need additional pertussis components added to induce high levels of protection. Anti-PT antibodies generated by NAVA diphtheria, tetanus, and acellular pertussis vaccine (DTaP) showed a positive correlation with protection against WHO-defined pertussis. The safety profiles for these vaccines showed low reactogenicity with no serious adverse events due to the vaccines.     

The evaluation of the mutagenic activity of pertussis vaccinal preparations]

Two vaccine preparations obtained from Bordetella pertussis, whole-cell vaccine constituting one of the components of adsorbed DPT vaccine and acellular vaccine, were tested for mutagenicity. The doses of the preparations covered the range 1-100 ED50. Ames' test and the metaphase analysis of marrow cells of C57BL/6J mice were used. The acellular preparation was also tested on thymectomized mice, taking into consideration chromosomal aberrations in marrow metaphases. Whole-cell and acellular pertussis vaccines did not induce mutations in Salmonella typhimurium and chromosomal aberrations in mouse marrow cells.     

Specificity and detection limit of a dermal temperature histamine sensitization test for absence of residual pertussis toxin in vaccines

Currently, an assay based on fatal sensitization of mice to histamine challenge is widely used for testing absence of residual pertussis toxin in acellular pertussis containing vaccines. For replacement of this lethal end-point assay, an alternative method based on body temperature measurement in mice has been presented, and in this study the specificity and detection limit of a dermal temperature-based assay were assessed. Test preparations containing pertussis toxin were prepared in aluminum-adjuvanted pertussis toxoid vaccine and injected intraperitoneally in histamine sensitive mice. Later the mice were challenged with histamine and the pertussis toxin-induced decrease in dermal temperature recorded. By comparison of mice treated with pertussis toxoid vaccine spiked with pertussis toxin with mice treated with pertussis toxoid vaccine alone, the assay gave a response that specifically could detect presence of pertussis toxin. The acellular pertussis containing vaccine did not interfere with the pertussis toxin-induced temperature response recorded. In tests for presence of pertussis toxin in the pertussis vaccine preparation, the detection limit of the assay was estimated to approximately 5 ng pertussis toxin per human dose of pertussis toxoid. The dermal temperature-based assay was found to be a valid method to be applied in routine quality control of vaccines.     

The characteristics of the development of immunity with a primary immunization complex using adsorbed DTP vaccine

The intensity of immunity, depending on immune response variants characterized by the definite composition of the T and B lymphocyte subpopulation in peripheral blood, was studied in 70 practically healthy young children after the primary complex of immunization with adsorbed DPT vaccine. The most stable immune reaction was shown to appear in children with the hyperergic and normoergic variants of immune response to diphtheria and tetanus toxoids, while the reaction to pertussis antigen was essentially weaker both after the second vaccination and after the first revaccination. In children with the hypoergic variant of immune response to all components of adsorbed DPT vaccine the resulting immune reaction was 2.5-3 times weaker than in children of other groups.     

Isolation of hemolytic cultures of Bordetella pertussis intended for the production of acellular pertussis preparations and the characterization of their biological properties

The heterogeneity of the population of B. pertussis laboratory strains with respect to the capacity of individual clones to lyse erythrocytes has been established. The complete or partial reduction of the antigens under study in nonhemolytic bacteria has been shown. The use of hemolytic cultures for the preparation of acellular pertussis vaccine makes it possible to increase the content of B. pertussis toxin in these vaccines.     

Limited controlled trial of the reactogenic properties of ADTP vaccines containing stab cultures as the pertussis component

The reactogenic properties of adsorbed DPT vaccine containing Bordetella pertussis cultures, grown by submerged cultivation, as the pertussis component were studied. The study revealed that the vaccine was low-reactogenic: no severe postvaccinal reactions were recorded in immunized children. The frequency and intensity of febrile and local reactions in children immunized with adsorbed DPT vaccine under trial and the commercial preparation commonly used in the USSR were identical, but considerably less pronounced than in children immunized with foreign vaccines having similar composition.     

Acellular and whole cell pertussis vaccines protect against the lethal effects of intracerebral challenge by two different T-cell dependent humoral routes

Athymic (nu/nu) and euthymic (+/nu) BALB/c mice were immunized with a whole cell pertussis vaccine or with an acellular vaccine which contained detoxified pertussis toxin (PT) and filamentous hemagglutinin (FHA). Only the euthymic mice were protected against intracerebral challenge with virulent Bordetella pertussis which implies involvement of T-cells. As a cell transfer from mice immunized with whole cell or acellular vaccine prior to the challenge did not protect naive euthymic recipients, cellular immunity seems to be non-protective as an effector mechanism. Mice could be protected passively against a challenge by administration of immune sera. Therefore, T-cell dependent humoral immune responses to B. pertussis appear to be crucial for protection. The humoral response was further studied with athymic and euthymic mice. In euthymic mice the whole cell vaccine induced antibodies to FHA, pililipopolysaccharides (LPS) and an outer membrane protein (OMP) preparation, whereas the acellular vaccine induced antibodies to PT, FHA and OMP. Both IgM and IgG could be detected. From the nude mice only those immunized with the whole cell vaccine showed an antibody response which consisted of low titres of IgM directed to LPS. Sera from both +/nu and nu/nu mice immunized with the whole cell vaccine were bactericidal in vitro. These data demonstrate that in the mouse model protection to intracerebral challenge with B. pertussis is T-cell dependent as is the humoral response to PT, FHA, OMP and pili. The T-independent B-cell activation by the whole cell preparation is due to the presence of LPS.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of different inactivating agents on the potency, toxicity and stability of pertussis vaccine

The effect of heat (56 degrees C for 10 min), formaldehyde (0.1% at 37 degrees for 24h), glutaraldehyde (0.05% at room temperature for 10 min), thimerosal (0.02% at 37 degrees C for 24h), acetone-I (three treatments at room temperature) and acetone-II (three treatments at room temperature and fourth treatment at 37 degrees C), when used as inactivating agents in the preparation of pertussis suspension, was studied with regard to potency, toxicity and stability. Five batches each of Bordetella pertussis strains 134 and 509 were used for the study. The thimerosal inactivated pertussis (TIP) preparation was 1.5-2 times more potent than the heat inactivated pertussis (HIP) preparation. The potency values of the formaldehyde inactivated pertussis (TIP) and glutaraldehyde inactivated pertussis (GIP) preparations were similar to those of the HIP preparation, while the potencies of the acetone-I treated pertussis (A(I)TP) and acetone-II treated pertussis (A(II)TP) preparations were about half those of the HIP preparation. The FIP preparation was the least toxic showing maximum weight gain in the mouse weight-gain test (MGWT), while the TIP preparation did not pass the MWGT. The weight gains shown the GIP, A(I)TP and A(II)TP preparations were greater than those shown by the HIP preparation. The potency of pertussis component in the adsorbed diphtheria-pertussis-tetanus (DPT) vaccine was stable at 4-8 degrees C and 25 degrees C for three months for all types of pertussis vaccine. There was about 54-65% loss in the potency of the samples after three months at 35 degrees C. The inactivating agents used in the manufacture of pertussis preparations had no effect on the stability of the vaccine.     

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.     

Comparative immunologic effectiveness of variants of the DTP vaccine

The immunological effectiveness of two batches of adsorbed DPT vaccine, the batch with the normal content of antigens (control) and the batch with the content of diphtheria and tetanus toxoids reduced to 20 Lf/ml and 5 BU/ml respectively (test batch), has been studied under the conditions of controlled trial. As a result, the reduction of the antigenic content of adsorbed DPT vaccine has been found to exert no negative influence on the immunological effectiveness of the diphtheria, tetanus, and pertussis components of this preparation under the conditions of the new immunization schedule.     

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.     

Oral immunogenicity of tomato-derived sDPT polypeptide containing Corynebacterium diphtheriae, Bordetella pertussis and Clostridium tetani exotoxin epitopes

DPT vaccine, designed to immunize against diphtheria, pertussis, and tetanus, has been shown to be effective in humans. Nevertheless, dissatisfaction with the whole-cell preparations is due to the reactogenicity, which has to lead to the development of new safer formulations. Previously, we described the expression in tomato of a plant-optimized synthetic gene encoding the recombinant polypeptide sDPT, containing mainly immunoprotective epitopes of the diphtheria, pertussis and tetanus exotoxins and two adjuvants. In this study, we examined whether the ingestion of tomato-derived sDPT protein induces specific antibodies in mice after three weekly doses scheme. A positive group immunized with DPT toxoids was included. Specific antibody levels were assessed in serum, gut and lung. Sera tested for IgG antibody response to pertussis, tetanus and diphtheria toxin showed responses to the foreign antigens; interestingly, the response to diphtheria epitope was similar to those observed in the positive group. We found higher IgG1 than IgG2a responses in serum. A modest IgG response was observed in the tracheopulmonary fluid. High response of IgA against tetanus toxin was evident in gut, which was statistically comparable to that obtained in the positive group. The levels of response in these groups were higher than those in mice that received wild-type tomato. These findings support the concept of using transgenic tomatoes expressing sDPT polypeptide as model for edible vaccine against diphtheria, pertussis, and tetanus.     

The effect of histamine on the rosette-forming ability of T-lymphocytes upon immunization with DPT vaccine and its components

The influence exerted by histamine on the capacity of T-lymphocytes for spontaneous rosette formation in intact animals and in animals immunized with adsorbed DPT vaccine and its components has been studied. Histamine at a concentration of 10(-3) M has been found to produce an inhibitory effect on the capacity of lymphocytes in the blood and spleen of guinea pigs immunized with adsorbed DPT vaccine and its components for spontaneous rosette formation. This effect of histamine has proved to be even more pronounced after the immunization of the animals with adsorbed DPT vaccine and Bordetella pertussis suspension, which is probably due to their sensitizing action.