A system-view of Bordetella pertussis booster vaccine responses in adults primed with whole-cell versus acellular vaccine in infancy.

The increased incidence of whooping cough worldwide suggests that current vaccination against Bordetella pertussis infection has limitations in quality and duration of protection. The resurgence of infection has been linked to the introduction of acellular vaccines (aP), which have an improved safety profile compared with the previously used whole-cell (wP) vaccines. To determine immunological differences between aP and wP priming in infancy, we performed a systems approach of the immune response to booster vaccination. Transcriptomic, proteomic, cytometric, and serologic profiling revealed multiple shared immune responses with different kinetics across cohorts, including an increase of blood monocyte frequencies and strong antigen-specific IgG responses. Additionally, we found a prominent subset of aP-primed individuals (30%) with a strong differential signature, including higher levels of expression for CCL3, NFKBIA, and ICAM1. Contrary to the wP individuals, this subset displayed increased PT-specific IgE responses after boost and higher antigen-specific IgG4 and IgG3 antibodies against FHA and FIM2/3 at baseline and after boost. Overall, the results show that, while broad immune response patterns to Tdap boost overlap between aP- and wP-primed individuals, a subset of aP-primed individuals present a divergent response. These findings provide candidate targets to study the causes and correlates of waning immunity after aP vaccination.

Hexavalent Vaccines in India: Current Status.

Hexavalent vaccines containing diphtheria, tetanus, pertussis, Haemophilus influenzae type b, poliomyelitis, and hepatitis B virus antigens have the potential to be used for the primary series in India (6, 10, 14 weeks of age) and the toddler booster dose. Three hexavalent vaccines are available in India: DTwP-Hib/HepB-IPV (wP-hexa), DTaP-IPV-HB-PRP~T(2aP-hexa), and DTaP-HBV-IPV/Hib (3aP-hexa). In the three published phase-3 Indian studies, pertussis 'vaccine response' rates 1 month after a 6-10-14-week primary series were 68.4-75.7% for wP-hexa, 93.8-99.3% for 2aP-hexa, and 97.0-100% for 3aP-hexa; seroprotection rates for the other five antigens were 88.2-100%, 49.6-100%, and 98.6-100%, respectively. Studies outside India show: good immunogenicity/safety after boosting dosing; immune persistence to age 4.5 years (2aP-hexa), 7-9 years (3aP-hexa) (all antigens), and 9-10 and 14-15 years, respectively (hepatitis B); and successful co-administration with other vaccines. Hexavalent vaccines could reduce the number of injections, simplify vaccination schedules, and improve compliance.

Modelling the effect of changes in vaccine effectiveness and transmission contact rates on pertussis epidemiology.

The incidence of the highly infectious respiratory disease named pertussis or whooping cough has been increasing for the past two decades in different countries, as in much of the highly vaccinated world. A decrease in vaccine effectiveness over time, especially when acellular vaccines were used for primary doses and boosters, and pathogen adaptation to the immunity conferred by vaccines have been proposed as possible causes of the resurgence. The contributions of these factors are not expected to be the same in different communities, and this could lead to different epidemiological trends. In fact, differences in the magnitude and dynamics of pertussis outbreaks as well as in the distribution of notified cases by age have been reported in various regions. Using an age-structured mathematical model designed by us, we evaluated how the changes in some of the parameters that could be related to the above proposed causes of disease resurgence - vaccine effectiveness and effective transmission rates - may impact on pertussis transmission. When a linear decrease in vaccine effectiveness (VE) was assayed, a sustained increase in pertussis incidence was detected mainly in infants and children. On the other hand, when changes in effective transmission rates (ßij) were made, a dynamic effect evidenced by the presence of large peaks followed by deep valleys was detected. In this case, greater incidence in adolescents than in children was observed. These different trends in the disease dynamics due to modifications in VE or ßij were verified in 18 possible scenarios that represent different epidemiological situations. Interestingly we found that both incidence trends produced by the model and their age distribution resemble the profiles obtained from data reported in several regions. The implications of these correlations are discussed.

[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.

Advances in the development of next-generation anthrax vaccines.

Anthrax, a disease of herbivores, only rarely infects humans. However, the threat of using Bacillus anthracis, the causative agent, to intentionally produce disease has been the impetus for development of next-generation vaccines. Two licensed vaccines have been available for human use for several decades. These are composed of acellular culture supernatants containing the protective antigen (PA) component of the anthrax toxins. In this review we summarize the various approaches used to develop improved vaccines. These efforts have included the use of PA with newer adjuvants and delivery systems, including bacterial and viral vectors and DNA vaccines. Attempts to broaden the protection afforded by PA-based vaccines have focused on adding other B. anthracis components, including spore and capsule antigens.

Lipopolysaccharide analogs improve efficacy of acellular pertussis vaccine and reduce type I hypersensitivity in mice.

Pertussis is an infectious disease of the respiratory tract that is caused by the gram-negative bacterium Bordetella pertussis. Although acellular pertussis (aP) vaccines are safe, they are not fully effective and thus require improvement. In contrast to whole-cell pertussis (wP) vaccines, aP vaccines do not contain lipopolysaccharide (LPS). Monophosphoryl lipid A (MPL) and Neisseria meningitidis LpxL2 LPS have been shown to display immune-stimulating activity while exerting little endotoxin activity. Therefore, we evaluated whether these LPS analogs could increase the efficacy of the aP vaccine. Mice were vaccinated with diphtheria-tetanus-aP vaccine with aluminum, MPL, or LpxL2 LPS adjuvant before intranasal challenge with B. pertussis. Compared to vaccination with the aluminum adjuvant, vaccination with either LPS analog resulted in lower colonization and a higher pertussis toxin-specific serum immunoglobulin G level, indicating increased efficacy. Vaccination with either LPS analog resulted in reduced lung eosinophilia, reduced eosinophil numbers in the bronchoalveolar lavage fluid, and the ex vivo production of interleukin-4 (IL-4) by bronchial lymph node cells and IL-5 by spleen cells, suggesting reduced type I hypersensitivity. Vaccination with either LPS analog increased serum IL-6 levels, although these levels remained well below the level induced by wP, suggesting that supplementation with LPS analogs may induce some reactogenicity but reactogenicity considerably less than that induced by the wP vaccine. In conclusion, these results indicate that supplementation with LPS analogs forms a promising strategy that can be used to improve aP vaccines.

Soluble CD30 and lymphocyte activation gene-3 (CD223), as potential serological markers of T helper-type cytokine response induced by acellular pertussis vaccine.

T cell responses are involved in vaccine-induced immunity to pertussis but no easy-to-monitor, serological markers are available to assess these responses. The lymphocyte activation gene-3 (CD223) molecule is present on, and released by, activated T helper (Th) 1 cells, whereas CD30 molecules have been associated with Th2 immune responses. Starting from the recent knowledge of the cytokine profile induced by pertussis vaccination, we examined the levels of soluble (s)CD223 and sCD30 proteins in child recipients of acellular pertussis (aP) and diphtheria-tetanus (DT) vaccines and in children receiving DT vaccine only, as control. The correlation of the two proteins with specific antibody and T cell responses was assessed. The main findings are: i) sCD223 and sCD30 levels are inversely related, suggesting that the two markers are the expression of different and counter-regulated T-cell responses; ii) sCD30 level correlated with induction of T cell proliferation to pertussis vaccine antigens and antibody response to pertussis toxin. Overall, sCD30 and sCD223 levels seem to be promising candidate markers to assess the induction of Th-type responses in vaccine recipients.

[Morphological alterations in animal organs after the injection of acellular pertussis vaccine with immunomodulator]. / Morfologicheskie izmeneniia v organakh zhivotnykh posle vvedeniia beskletochnoi kokliushnoi vaktsiny s immunomoduliatorom.

Toxic properties of acellular pertussis vaccine (APV) and morphological changes in white mice in response to intramuscular injection of APV (without or with immunomodulator glucosaminylmuramyl dipeptide-GMDP) were under study. APV used in these experiments was developed at the Mechnikov Research Institute for Vaccines and Sera (the Russian Acad. Med. Sci.) on the basis of Bordetella pertussis cultures in synthetic fluid culture media. In experiments on acute and chronic toxicity of APV (without GMDP) increased tissue immunity reactions in spleen, thymus, liver, lungs and intestinal wall was detected. There was no difference in immunomorphological reactions in mice receiving APV with different doses of GMDP, but some difference was observed in time dynamics of tissue immunity reactions. A small dose of GMDP should be preferred (0.0001 microgram) which results in gradual growth of tissue immunity reactions less pronounced toxic reactions caused be the APV injection.

Using the Australian Childhood Immunisation Register to track the transition from whole-cell to acellular pertussis vaccines.

From 1997 to 1999, Australia changed from a whole-cell based pertussis vaccination program to an acellular one. This paper tracks the transition from whole-cell to acellular pertussis vaccines by calculating the number of whole cell (DTPw) and acellular (DTPa) pertussis vaccines recorded on the Australian Childhood Immunisation Register (ACIR) each month from January 1996 to August 2000. The number of combined diphtheria-tetanus (CDT) vaccines, recommended where DTP is contraindicated and for the fifth dose prior to 1994, was also calculated. The use of DTPa increased following its licensing in 1997, with a corresponding decrease in the use of DTPw. The increase was initially greatest in its use as a fourth and fifth dose, for which it was funded at a national level in 1997. Subsequently, a steep increase in its use for the first three doses followed in 1999, coinciding with it becoming free of charge for infants nationally. The use of CDT has decreased markedly since January 1996 and, since March 2000, fewer than 100 CDT vaccines per month were recorded on the ACIR, suggesting that this vaccine is not being inappropriately used.

A quantitative analysis for the ADP-ribosylation activity of pertussis toxin: an enzymatic-HPLC coupled assay applicable to formulated whole cell and acellular pertussis vaccine products.

The majority of the biological effects of pertussis toxin (PT) are the result of a toxin-catalyzed transfer of an adenosine diphosphate-ribose (ADP-ribose) moiety from NAD(+)to the alpha-subunits of a subset of signal-transducing guanine-nucleotide-binding proteins (G-proteins). This generally leads to an uncoupling of the modified G-protein from the corresponding receptor and the loss of effector regulation. This assay is based on the PT S1 subunit enzymatic transfer of ADP-ribose from NAD to the cysteine moiety of a fluorescent tagged synthetic peptide homologous to the 20 amino acid residue carboxyl-terminal sequence of the alpha-subunit of the G(i3)protein. The tagged peptide and the ADP-ribosylated product were characterized by HPLC/MS and MS/MS for structure confirmation. Quantitation of this characterized ADP-ribosylated fluorescently tagged peptide was by HPLC fluorescence using Standard Addition methodology. The assay was linear over a five hr incubation period at 20 degrees C at PT concentrations between 0.0625 and 4.0 microg/ml and the sensitivity of the assay could be increased several fold by increasing the incubation time to 24 h. Purified S1 subunit of PT exhibited 68.1+/-10.1% of the activity of the intact toxin on a molar basis, whereas the pertussis toxin B oligomer, the genetically engineered toxoid, (PT-9K/129G), and several of the other components of the Bordetella pertussis organism possessed little (<0.6%) or no detectable ribosylation activity. Commonly used pertussis vaccine reference materials, US PV Lot #11, BRP PV 66/303, and BRP PV 88/522, were assayed by this method against Bordetella pertussis Toxin Standard 90/518 and demonstrated to contain, respectively, 0.323+/-0.007, 0.682+/-0.045, and 0.757+/-0.006 microg PT/ml (Mean+/-SEM) or in terms of microg/vial: 3.63, 4.09 and 4.54, respectively. A survey of several multivalent pertussis vaccine products formulated with both whole cell as well as acellular components indicated that products possessed a wide range of ribosylation activities. The pertussis toxin S1 subunit catalyzed ADP- ribosylation of the FAC-Galpha(i3)C20 peptide substrate and its subsequent quantitation by HPLC was demonstrated to be a sensitive and quantitative method for measuring intrinsic pertussis toxin activity. This methodology not only has the potential to be an alternative physicochemical method to replace existing bioassay methodology, but has the added advantage of being a universal method applicable to the assay of pertussis toxin in both whole cell and acellular vaccines as well as bulk and final formulated vaccine products. Acceptance of this method by regulatory agencies and industry as a credible alternative to existing methods would, however, require validation in an international collaborative study against the widely accepted bioassay methods.

Analysis of Bordetella pertussis isolates collected in Japan before and after introduction of acellular pertussis vaccines.

Because of recent concern that whole-cell pertussis vaccination can drive antigenic divergence of circulating isolates of Bordetella pertussis, we compared 12 clinical isolates of B. pertussis collected in Japan, the first country to introduce acellular pertussis vaccines, with the vaccine strain. We used pulsed-field gel electrophoresis, sequencing of ptx and prn genes and expression of fimbriae. Most of the isolates collected before or after introduction of acellular vaccine possess similar restriction patterns. They contain ptx genes and prn alleles similar to the vaccine strain and to European isolates collected before the introduction of vaccination. Two recently collected isolates exhibiting a different pulsed-field gel electrophoresis pattern possess ptxS1 and prn alleles similar to the alleles harbored by European isolates circulating currently. Our preliminary results suggest that, if acellular pertussis vaccine-induced antigenic divergence exists, it is likely to be a slow or rare process.