In vitro alternative for reactogenicity assessment of outer membrane vesicle based vaccines.

Intrinsic or added immune activating molecules are key for most vaccines to provide desired immunity profiles but may increase systemic reactogenicity. Regulatory agencies require rabbit pyrogen testing (RPT) for demonstration of vaccine reactogenicity. Recently, the monocyte activation test (MAT) gained popularity as in vitro alternative, yet this assay was primarily designed to test pyrogen-free products.

Naturally circulating pertactin-deficient strains induce distinct gene expression and inflammatory signatures in human dendritic cells.

Respiratory infections caused by are reemerging despite high pertussis vaccination coverage. Since the introduction of the acellular pertussis vaccine in the late twentieth century, circulating strains increasingly lack expression of the vaccine component pertactin (Prn). In some countries, up to 90% of the circulating strains are deficient in Prn.

The Role of Virulence Proteins in Protection Conferred by Outer Membrane Vesicle Vaccines.

The limited protective immunity induced by acellular pertussis vaccines demands development of novel vaccines that induce broader and longer-lived immunity. In this study, we investigated the protective capacity of outer membrane vesicle pertussis vaccines (omvPV) with different antigenic composition in mice to gain insight into which antigens contribute to protection. We showed that total depletion of virulence factors ((-) mode) in omvPV led to diminished protection despite the presence of high antibody levels.

Proteome Analysis Is a Valuable Tool to Monitor Antigen Expression during Upstream Processing of Whole-Cell Pertussis Vaccines.

Physicochemical and immunochemical assays were applied to substantiate the relation between upstream processing and the quality of whole-cell pertussis vaccines. Bordetella pertussis bacteria were cultured on a chemically defined medium using a continuous cultivation process in stirred tank reactors to obtain uniform protein expression. Continuous culture favors the consistent production of proteins known as virulence factors.

Surface display of a borrelial lipoprotein on meningococcal outer membrane vesicles.

Outer Membrane Vesicles (OMVs) are gaining attention as vaccine candidates. The successful expression of heterologous antigens in OMVs, with the OMV functioning both as adjuvant and delivery vehicle, has greatly enhanced their vaccine potential. Since there are indications that surface exposed antigens might induce a superior immune response, targeting of heterologous antigens to the OMV surface is of special interest.

Immunoproteomic Profiling of Bordetella pertussis Outer Membrane Vesicle Vaccine Reveals Broad and Balanced Humoral Immunogenicity.

The current resurgence of whooping cough is alarming, and improved pertussis vaccines are thought to offer a solution. Outer membrane vesicle vaccines (omvPV) are potential vaccine candidates, but omvPV-induced humoral responses have not yet been characterized in detail. The purpose of this study was to determine the antigen composition of omvPV and to elucidate the immunogenicity of the individual antigens.

Acellular pertussis vaccine based on outer membrane vesicles capable of conferring both long-lasting immunity and protection against different strain genotypes.

Despite high vaccination coverage rates, pertussis continues to be a global concern, with increased incidence widely noted. The current pertussis epidemiologic situation has been mainly attributed to waning immunity and pathogen adaptation. To improve the disease control, a new generation of vaccines capable to overcome those weaknesses associated to the current vaccines need to be developed.

Genome-wide gene expression analysis of Bordetella pertussis isolates associated with a resurgence in pertussis: elucidation of factors involved in the increased fitness of epidemic strains.

Bordetella pertussis (B. pertussis) is the causative agent of whooping cough, which is a highly contagious disease in the human respiratory tract. Despite vaccination since the 1950s, pertussis remains the most prevalent vaccine-preventable disease in developed countries.

An improved whole cell pertussis vaccine with reduced content of endotoxin.

An improved whole cell pertussis vaccine, designated as Plow, which is low in endotoxicity due to a chemical extraction of lipo-oligosaccharide (LOS) from the outer membrane, was evaluated for safety, immunogenicity and potency, comparatively to a traditional whole cell pertussis vaccine. Current whole cell pertussis vaccines are effective but contain large quantities of endotoxin and consequently display local and systemic adverse reactions after administration. Endotoxin is highly inflammatory and contributes considerably to the reactogenicity as well as the potency of these vaccines.

Resurgence of pertussis calls for re-evaluation of pertussis animal models.

Pertussis has recently re-emerged in well-vaccinated populations most likely due to a combination of pathogen adaptation and waning of vaccine-induced pertussis immunity. Changes in genomic content of the etiologic agent, Bordetella pertussis, observed in the postvaccination era can have a bearing on the efficacy of vaccines currently in use. Moreover, protective immune responses in vaccinees wane gradually depending on their originally induced size and breadth, and memory responses may not be as regularly boosted by circulating strains as was the case in the prevaccination era.

Nonclinical vaccine safety evaluation: advantages of continuous temperature monitoring using abdominally implanted data loggers.

Fever has been reported as the most common adverse event after vaccination in infants and children. For this reason it is important that, prior to clinical testing of a new vaccine, change in body temperature following vaccination is tested carefully in nonclinical animal studies. Since both the timing and the height of the temperature peak after vaccination may differ from vaccine to vaccine, it is important that the time point for body temperature measurement should be chosen on a case-by-case basis with sufficient knowledge of the specific vaccine.

Outer membrane vesicles obtained from Bordetella pertussis Tohama expressing the lipid A deacylase PagL as a novel acellular vaccine candidate.

In an effort to devise a safer and effective pertussis acelullar vaccine, outer membrane vesicles (OMVs) were engineered to decrease their endotoxicity. The pagL gene from Bordetella bronchiseptica, which encodes a lipid A 3-deacylase, was expressed in Bordetella pertussis strain Tohama I. The resulting OMVs, designated OMVs(BpPagL), contain tetra- instead of penta-acylated LOS, in addition to pertussis surface immunogens such as pertactin and pertussis toxin, as the wild type OMVs.

Development of an animal-component free medium for vero cells culture.

This work describes the development of an animal-component free medium (IPT-AFM) that allows an optimal growth of Vero cells, an adherent cell line used for the production of viral vaccines. Statistical experimental design was applied to identify crucial nutrients that affect cell growth. Using Medium 199 or MEM as a basal medium, a serum-free medium (SFM) referred as IPT-SFM that only enclosed transferrin as a component of animal origin was developed at first.

A novel animal-component-free medium for rabies virus production in Vero cells grown on Cytodex 1 microcarriers in a stirred bioreactor.

Vero cells growth and rabies production in IPT-AF medium, a property animal-component-free medium are described in this work. Kinetics of cell growth and rabies virus (strain LP 2061) production were first conducted in spinner flasks. Over eight independent experiments, Vero cell growth in IPT-AF medium, on 2 g/l Cytodex 1 was consistent.

Reducing variation in a rabbit vaccine safety study with particular emphasis on housing conditions and handling.

This paper describes the results of a study of the effects of modified housing conditions, conditioning and habituation on humans using a rabbit model for monitoring whole-cell pertussis vaccine (pWCV)-induced adverse effects. The study has been performed with reference to previous vaccine safety studies of pWCV in rabbits in which results were difficult to interpret due to the large variation in experimental outcome, especially in the key parameter deep-body temperature (T(b)). Certain stressful laboratory conditions, as well as procedures involving humans, e.

Improving the cellular pertussis vaccine: increased potency and consistency.

Although Europe, Canada and the US have switched from cellular to acellular pertussis vaccines, most developing countries will continue to use the more cost effective cellular vaccine. Consistency of production however is the typical problem inherent to cellular vaccines. Optimising the production process of cellular pertussis bulk suspensions using product potency as a measure is not possible, since the mandatory animal test to measure potency has little discriminatory power.

A microcarrier cell culture process for propagating rabies virus in Vero cells grown in a stirred bioreactor under fully animal component free conditions.

Rabies virus strain production in Vero cells grown on Cytodex 1 in a 2 L stirred tank bioreactor and in a medium free of components of human or animal origin (VP-SFM) is described. Cell banking procedure in VP-SFM supplemented with an animal components free mixture (10%DMSO+0.1%methylcellulose) was reported and cell growth after revitalization was assessed.

Pertussis Serological Potency Test as an Alternative to the Intracerebral Mouse Protection Test: Development, Evaluation and Validation.

We have developed the Pertussis Serological Potency Test (PSPT) as an alternative to potency testing of pertussis Whole Cell Vaccines (WCV) in the intracerebral Mouse Protection Test (MPT). The PSPT is based on the humoral antibody response against the whole range of B. pertussis surface-antigens per vaccine dose and correlates well with the MPT.