Increase in intradermal vascular permeability caused by pertussis toxin from Bordetella pertussis

Rabbits that were injected intradermally with pertussis toxin (PT), produced from Bordetella pertussis, showed slight edema and erythema at the injection sites, but not hemorrhage nor necrosis. The edema lesions were stained blue by the intravenous injection of Pontamine Sky Blue 6B dye, suggesting that PT caused increased vascular permeability, similarly to the permeability factor (PF) of cholera toxin. The reaction of the PF of PT could be determined by measuring the diameter of the blue area. The diameter of the blue area bore a good linear relationship to the logarithm of the dose of PT. The activity of the PF was neutralized by anti-PT rabbit serum. Detoxification of PT with formalin did not increase the vascular permeability, but reverted pertussis toxoid showed a PF reaction in proportion to the reverted leukocytosis-promoting and histamine-sensitizing activities of PT. The supernate of a Bordetella pertussis culture also induced a PF reaction and the reaction could be made clear by heating the supernate at 56 C for 30 min, but the supernate of Bordetella bronchiseptica did not induce the reaction at all.     

Acetone-treated pertussis vaccine--a potent and safer new pertussis vaccine

A vaccine was prepared from the growth of Bordetella pertussis by repeated treatment with acetone. The vaccine has been designated as acetone-treated pertussis vaccine (ATPV). A total of ten batches of ATPV were prepared, five each from B. pertussis strains 134 and 509. These strains are routinely employed at this Institute for the production of conventional whole-cell pertussis vaccine (WCPV) for blending in diphtheria-pertussis-tetanus vaccine. The mouse protective and histamine sensitizing activities of ATPV and WCPV were compared. The ATPV showed 1.5- to 2-fold higher potency than the WCPV. The histamine sensitizing activity of ATPV was much reduced compared with that of the WCPV. No appreciable difference was observed in the results of a mouse weight-gain tests between the ATPV and WCPV. The details of the preparation of ATPV have been described. Because of higher potency and reduced histamine sensitizing activity, the ATPV may prove more acceptable in immunization programmes against pertussis, even in countries where WCPV is unpopular due to its suspected reactogenicity.     

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.     

Bordetella pertussis bacteriophage

For the first time Bordetella pertussis bacteriophage was isolated, and its presence was confirmed by electron microscopy and by agar layer titration. The lysogenic strains were activated by their treatment with mitomycin C in a dose of 4.5 mg/ml. The phage system of the Bordetella genus, heretofore unknown, has been revealed: Bordetella pertussis phage lyzed all the tested strains of Bordetella parapertussis (25 strains) and could be passaged in these strains. The phage formed turbid and transparent negative colonies 0.1 mm and 0.15 mm in size. The phage titer (e. g., in strain No. 3865) was 1 X 10(10). The lysogenic variants of Bordetella pertussis, capable of spontaneous release of the phage, were obtained. These variants were characterized by changes in some of their phenotypical properties, e.g., the increased content of certain toxic substances and increased virulence.     

Seroprevalence of pertussis in The Netherlands: evidence for increased circulation of Bordetella pertussis

Background

In many countries, the reported pertussis has increased despite high vaccination coverage. However, accurate determination of the burden of disease is hampered by reporting artifacts. The infection frequency is more reliably estimated on the basis of the prevalence of high IgG concentrations against pertussis toxin (IgG-Ptx). We determined whether the increase in reported pertussis in the last decade is associated with an increase in the number of infections.

Methodology/Principal Findings

In a cross-sectional population-based serosurveillance study conducted in 2006-07, from a randomly selected age-stratified sample of 7,903 persons, serum IgG-Ptx concentrations were analyzed using a fluorescent bead-based multiplex immuno assay. In 2006-07, 9.3% (95%CI 8.5-10.1) of the population above 9 years of age had an IgG-Ptx concentration above 62.5 EU/ml (suggestive for pertussis infection in the past year), which was more than double compared to 1995-96 (4.0%; 95%CI 3.3-4.7). The reported incidence showed a similar increase as the seroprevalence between both periods.

Conclusions

Although changes in the vaccination program have reduced pertussis morbidity in childhood, they have not affected the increased infection rate in adolescent and adult pertussis. Indeed, the high circulation of B. pertussis in the latter age-categories may limit the effectiveness of pediatric vaccination.     

Production of cell mass and pertussis toxin by Bordetella pertussis.

The cultivation of Bordetella pertussis affects production of pertussis toxin and biomass. Comparison of batch mode, chemostat operation and pHstat-turbidostatic control showed that productivities for the continuous process were greater than that for the batch operation. Continuous operation in balanced growth at the maximum specific growth rate, provided by the pHstat, resulted in the maximum specific production rate. Because of the strong association of pertussis toxin synthesis and cell growth, the concentration of toxin in the effluent of the continuous processes was greater than the maximum obtained in the batch bioprocess. An expanded Luedeking-Piret model of product formation kinetics fits the observed chemostat data and demonstrates that the production of pertussis toxin from the culture of B. pertussis is predominantly growth associated.     

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.     

Highly sensitive histamine-sensitization test for residual activity of pertussis toxin in acellular pertussis vaccine

Histamine-sensitization test method based on histamine-sensitizing death is widely used for controlling residual activity of pertussis toxin in acellular pertussis vaccines. The test method evaluates the residual activity according to the death of mice injected with a test vaccine after histamine challenge and the test result, therefore, depends on the sensitivity of mice. A highly sensitive test method based on change in rectal temperature of mice has been used in Japan for many years but has limited feasibility in other countries. We examined the possibility of a test method using dermal temperature measured by infrared thermometer to reduce animal suffering instead of rectal temperature. The dermal temperature method was shown to be as sensitive as the rectal temperature method. Furthermore, the dermal as well as rectal temperature methods can evaluate the activity of a test vaccine in relative to a reference preparation so as to allow direct comparison of the test results among different laboratories. The activity by means of the dermal temperature method was also found to be well consistent with that by the rectal temperature method.     

Use of specific Bordetella pertussis antibodies in immunoenzyme analysis for detecting the pertussis antigen

The competitive EIA technique with the use of peroxidase-labeled B. pertussis antigen has been developed. The data obtained in our investigations suggest the possibility of using this technique for the detection of B. pertussis antigen in faucial smears obtained from patients.     

Large scale cultivation of Bordetella pertussis in submerged culture for production of pertussis toxin

Summary Large quantities of purified Bordetella pertussis toxin were required to develop an investigational toxoid vaccine. To overcome the difficulties associated with the large scale growth of Bordetella pertussis in submerged culture, we employed an aeration strategy using compressed oxygen and an antifoam agent. The microorganism grown in this way in 1001 batches for 20–24 h yielded 4–6 mg·1^-1 pertussis toxin.     

Mutants in the ptlA-H genes of Bordetella pertussis are deficient for pertussis toxin secretion

The nine ptl genes (A-I) are required for efficient secretion of pertussis toxin past the outer membrane. Mutations were made in ptlA-H by filling in unique restriction sites, generating in-frame deletions, or inserting a FLAG epitope tag. The mutations were cloned into a suicide shuttle plasmid containing the ptxptl operon and introduced into the adenylate cyclase locus of the chromosome of a Bordetella pertussis strain deleted for ptx. The wild-type ptxptl operon restored pertussis toxin expression and secretion. The ptl mutant constructs also restored expression of periplasmic pertussis toxin to the ptx deletion strain but the mutants had a statistically significant decrease in secretion of pertussis toxin of between 5- to 35-fold, suggesting all of the ptl genes must be intact for efficient pertussis toxin secretion. The mutations were also introduced into the adenylate cyclase locus of a wild-type ptxptl strain, resulting in a ptl diploid strain. The PtlC, PtlD, PtlE, PtlF, PtlG and PtlH mutants exerted dominance over the wild-type allele.     

Antitoxin in human pertussis immune globulins

The level of antitoxin i.e. neutralizing antibodies to pertussis toxin, or lymphocytosis promoting factor, was determined in six pertussis immune globulin preparations from different manufactures. A comparison with antitoxin levels after natural pertussis disease in adults showed that pertussis immune globulins did not contain more antitoxin than convalescent phase sera, i.e. they had very low antitoxin content for specific immune globulins. Agglutinin and anti-FHA titres were relatively higher in immune globulins, probably reflecting a difference between the antibody response elicited by whole cell vaccines used for hyperimmunization in immune globulin production and by natural disease. The low antitoxin content of currently available pertussis immune globulin preparations could explain the inefficacy or conflicting results obtained with these products in prophylaxis and therapy of whooping cough.     

Lipopolysaccharides in a traditional pertussis vaccine

Analysis of the lipopolysaccharide (LPS, endotoxin) in cell sonicates of four Danish vaccine strains of Bordetella pertussis (3803, 3825, 3843 and 3860) and of purified strain 3803 LPS in sodium dodecyl sulphate-polyacrylamide gel electrophoresis by silver staining, showed identical profiles. The LPS profile revealed a dominant, brownish LPS II band and a minor, faster-migrating, black-stained LPS I band. However, the ratio of LPS I to LPS II in the preparation of purified LPS differed slightly from the cell sonicates. Using marker LPS, the molecular weights of LPS I and LPS II were estimated at 5.4 and 6.0 kD, respectively. Seven different lots of whole cell pertussis vaccine were assayed for LPS in the Limulus Amoebocyte Lysate test and were found to contain 0.9-2.8 micrograms LPS/ml. No significant difference in the content of LPS in similar dilutions of the individual strains was observed. In addition, the distribution of free and cell-bound LPS in four pertussis vaccines was investigated. Most of the LPS was found to exist as free LPS. During several months, the course of both LPS and pertussis toxin (Pt) release in freshly killed B. pertussis preparations was followed. In the first few weeks, 35-50% of the LPS was released and after 5-6 months of storage 60-80% had been released. In contrast, less than 10% of the biologically active pertussis toxin was released during the experimental period. The possibility of producing a safer whole cell pertussis vaccine by reducing the amount of free LPS without reducing the protective value correspondingly is discussed.