Expression of phosphofructokinase in Neisseria meningitidis.

Neisseria meningitidis serogroup B is a pathogen that can infect diverse sites within the human host. According to the N. meningitidis genomic information and experimental observations, glucose can be completely catabolized through the Entner-Doudoroff pathway and the pentose phosphate pathway.

A practical approach for exploration and modeling of the design space of a bacterial vaccine cultivation process.

A licensed pharmaceutical process is required to be executed within the validated ranges throughout the lifetime of product manufacturing. Changes to the process, especially for processes involving biological products, usually require the manufacturer to demonstrate that the safety and efficacy of the product remains unchanged by new or additional clinical testing. Recent changes in the regulations for pharmaceutical processing allow broader ranges of process settings to be submitted for regulatory approval, the so-called process design space, which means that a manufacturer can optimize his process within the submitted ranges after the product has entered the market, which allows flexible processes.

Modeling Neisseria meningitidis B metabolism at different specific growth rates.

Neisseria meningitidis is a human pathogen that can infect diverse sites within the human host. The major diseases caused by N. meningitidis are responsible for death and disability, especially in young infants.

Evaluation of a critical process parameter: oxygen limitation during cultivation has a fully reversible effect on gene expression of Bordetella pertussis.

Modern (bio)pharmaceutical process development requires thorough investigation of all process parameters that are critical to product quality. The impact of a disturbance of such a parameter during processing needs to be known so that a rational decision can be made about the release of the product. In cultivation processes the dissolved oxygen (DO) concentration is generally accepted as being a critical parameter.

Scale-up for bulk production of vaccine against meningococcal disease.

At the Netherlands Vaccine Institute (NVI) a vaccine against Neisseria meningitidis serogroup B organisms based on different porA subtypes contained in outer membrane vesicles (OMVs) is in advanced stage of development and will be evaluated in clinical trial studies in the near future. In order to meet the expected demand for product, the current biopharmaceutical production process is being scaled-up. This study describes the scale-up approach for the upstream process and the resulting bioreactor design and operation strategy leading towards a feasible solution for bulk production of a vaccine against meningococcal disease.

Modeling Neisseria meningitidis metabolism: from genome to metabolic fluxes.

Background: Neisseria meningitidis is a human pathogen that can infect diverse sites within the human host. The major diseases caused by N. meningitidis are responsible for death and disability, especially in young infants.

PAT for vaccines: the first stage of PAT implementation for development of a well-defined whole-cell vaccine against whooping cough disease.

Since variation in process time and process output is commonly accepted to be inevitable for biological processes, application of Process Analytical Technologies (PAT) on these processes is challenging. In this paper the applicability of PAT on the cultivation of Bordetella pertussis bacteria as part of the manufacture of a vaccine against whooping cough disease is investigated. Scrutinizing and eliminating the most prominent sources of variance make the cultivation process step highly reproducible.

Randomised, controlled trial with the trypsin-modified inactivated poliovirus vaccine: assessment of intestinal immunity with live challenge virus.

The enhanced potency inactivated poliovirus vaccine (E-IPV) was modified to contain trypsin-treated type 3 poliovirus (PV3), strain Saukett, as the type 3 component (TryIPV). This pilot vaccine was previously shown to redistribute the vaccine-induced antibody specificities in mice to mimic those seen in man after poliovirus infection. Groups of infants were then immunised with three doses of TryIPV or E-IPV in a randomised, double-blind trial.

In vitro determination of antigen quality: biosensor analysis and fluorescence spectroscopy.

We are probing the potential of two techniques to monitor the quality of antigens in vitro. Structural and conformational differences between diphtheria toxin and toxoid are detected via biosensor analysis (BIA-core) and fluorescence spectrometry. With BIA-core the interaction kinetics between toxin and toxoid and a monoclonal antibody were established.

Potency of wild-type or sabin trivalent inactivated poliovirus vaccine, by enzyme-linked immunosorbent assay using monoclonal antibiotics specific for each antigenic site.

Potency testing of inactivated poliovirus vaccine (IPV) is hampered by the absence of a standardized in vitro test, as well as the lack of a generally accepted quantitative animal test. In vitro tests must be able to measure selectively the content of the "D" antigen in the vaccine which includes virus neutralizing antibodies. We tested 12 poliovirus type 1, 12 type 2 and six type 3, D antigen-specific monoclonal mouse antibodies (mAb) for use in the enzyme-linked immunosorbent assay (ELISA).

A new WHO International Reference Reagent for use in potency assays of inactivated poliomyelitis vaccine.

Assays of the potency of inactivated poliovirus vaccine require the use of an appropriate reference reagent. Preparation 91/574 was shown by international collaborative study to be suitable for determination of antigenic content and immunogenicity of inactivated poliovirus vaccines by in vitro and in vivo assays, respectively. The reagent is a trivalent blend of formaldehyde-inactivated monovalent pools of poliovirus type 1 (Mahoney) poliovirus type 2 (MEF-1) and poliovirus type 3 (Saukett).

Inactivated poliovirus vaccine protects transgenic poliovirus receptor mice against type 3 poliovirus challenge.

Transgenic (Tg) mice expressing the human poliovirus receptor (PVR) were vaccinated with inactivated poliovirus vaccine (IPV) and evaluated for induced immunity against type 3 poliomyelitis. One injection of monovalent type 3 IPV elicited protective immunity against wild-type poliovirus. In contrast, 2 injections of trivalent IPV were required for protection.

Immunogenicity of a pilot inactivated poliovirus vaccine with trypsin-treated type 3-component.

A modified trivalent enhanced potency IPV (E-IPV) containing trypsin-treated PV3/Saukett as the type 3-component (TryIPV) was evaluated in preclinical and Phase I and Phase II clinical trials with the regular E-IPV as a control. In Balb/c mice, TryIPV-induced antibodies targeted outside the trypsin-sensitive antigenic site, as expected. Immunogenicity of TryIPV in man, as judged by a booster response in neutralizing antibodies to type 1, 2 or 3 poliovirus, was as good as that of the regular E-IPV in both adults and children.

Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

The death rate of Vero cells grown on Cytodex-3 microcarrierswas studied as a function of the gas flow rate in a smallair-lift loop reactor. The death rate may be described byfirst-order death-rate kinetics. The first-order death-rateconstant as calculated from the decrease in viable cells, theincrease in dead cells and the increase in LDH activity islinear proportional to the gas flow rate, with a specifichypothetical killing volume in which all cells are killed ofabout 2.

Current good manufacturing practice in plant automation of biological production processes.

The production of biologicals is subject to strict governmental regulations. These are drawn up in current good manufacturing practices (cGMP), a.o.

Single shot with tetanus toxoid in biodegradable microspheres protects mice despite acid-induced denaturation of the antigen.

Tetanus toxoid encapsulated in microspheres consisting of biodegradable polyesters, prepared by four different manufacturers were evaluated with respect to antigenic load, in vitro release pattern, antigen integrity and immunogenicity. In vitro release studies over periods up to 140 days indicated that only during the first days tetanus toxoid was released. Although some preparations were designed to release their antigen content in a pulsatile manner, this was never observed in vitro.

On-line estimation of the biomass activity during animal-cell cultivations.

A software sensor was developed to determine the volumetric biomass activity of animal cell cultivations on-line. It was based on the on-line estimation of the ATP-production rate from the oxygen uptake and the lactic-acid production rate. The sensor was verified for a batch culture of Vero cells, and a batch and a continuous culture of hybridoma cells.

Death rate in a small air-lift loop reactor of vero cells grown on solid microcarriers and in macroporous microcarriers.

The death rate of Vero cells grown on Cytodex-3 microcarriers was studied as a function of the gas flow rate in a small air-lift loop reactor. The death rate may be described by first-order death-rate kinetics. The first-order death-rate constant as calculated from the decrease in viable cells, the increase in dead cells and the increase in LDH activity is linear proportional to the gas flow rate, with a specific hypothetical killing volume in which all cells are killed of about 2·10(-3) m(3) liquid per m(3) of air bubbles.

A combined cell-cycle and metabolic model for the growth of hybridoma cells in steady-state continuous culture.

The Model presented in this work demonstrates the combination of cell-cycle model with a model describing the growth and conversion kinetics of hybridoma cells in a steady-state continuous culture. The cell-cycle model is based upon a population balance model as described by Cazzador et al. and assumes the existence of a cycling-and apoptotic-cell population, which together form the viable-cell population.

Immunogenicity of trypsin treated type 2 and type 3 poliovirus in rats.

Oral polio vaccine will encounter the proteolytic enzyme trypsin during administration but inactivated polio vaccine not. To investigate the effect on the humoral immune response, rats were immunized intramuscularly with trypsin treated type 2 and type 3 poliovirus. IgG and IgM responses were determined as well as the neutralizing antibody titer.

Simultaneous administration of oral rhesus-human reassortant tetravalent (RRV-TV) rotavirus vaccine and oral poliovirus vaccine (OPV) in Thai infants.

Rhesus-human reassortant tetravalent (RRV-TV) oral rotavirus vaccine was given at the same time as oral poliovirus vaccine (OPV) or inactivated parenteral poliovirus vaccine (IPV) to Thai infants at 2, 4 and 6 months of age. Sera for rotavirus antibody studies were taken prior to and one month after each vaccination. After the first dose of vaccine at 2 months of age, 37% of the infants receiving rotavirus vaccine with IPV but only 10% of those receiving it with OPV showed a seroconversion by rotavirus IgA ELISA antibody test (p < 0.

Batch control system vaccines: BCSV : A new man machine interface for bioreactors.

The Batch Control System for Vaccines (BCSV), a new Man Machine Interface (MMI) for the control of cultivations in bioreactors, was developed according to SP-88. SP-88 is the ISA standard for Batch Control Systems. Among others, SP-88 supplied the concept of recipes, which organize and specify the monitoring and control requirements for manufacturing.

A method for simultaneous determination of solubility and transfer coefficient of oxygen in aqueous media using off-gas mass spectrometry.

A static method was developed that simultaneously determined the solubility of oxygen and the oxygen-transfer coefficient in a stirred bioreactor. It was based on the static method developed by van Sonsbeek et al. to determine the ka in a liquid-impelled loop reactor.