Gene‐expression‐based quality scores indicate optimal harvest point in Bordetella pertussis cultivation for vaccine production

Abstract

The evolution of vaccine product quality during batch cultivation of Bordetella pertussis, the causative agent of whooping cough, was investigated with the goal to determine the optimal harvest point. The process was explored by measuring mRNA expression at frequent intervals during cultivation. The genes that are involved in virulence are already known for this product and changes in their expression levels are proposed to be indicative for product quality. A quantitative product quality score is calculated based on the expression levels of these virulence genes, which allows comparison of expected product quality between culture samples. Product quality scores were maximal throughout the logarithmic growth phase, but dropped significantly at the start of the stationary phase. This showed that the decreasing lactate and glutamate concentrations towards the end of the batch are critical for product quality. On-line measurement of these nutrients allows the cultivation process to be harvested at the optimal harvest point, increasing process robustness and consistency.

Inherent Differential Propensity of Dental Pulp Stem Cells Derived from Human Deciduous and Permanent Teeth

“…Van de Waterbeemd et al (40) used this PCA method to study the optimal harvest point in bacterial vaccine production, and Liu et al (41) described the detection of endogenous signaling activation pathways by an oncogenic stimulus. Here we show yet another novel facet of PCA method to distinguish between gene expression pattern of SCD and DPSCs.…”

Vaccine-Mediated Activation of Human TLR4 Is Affected by Modulation of Culture Conditions during Whole-Cell Pertussis Vaccine Preparation

“…pertussis bacteria harvested at different time points after sulfate addition were analysed using full genome B . pertussis DNA-microarrays according to the procedure described in detail elsewhere [12](Metz et al . submitted for publication).…”

“…submitted for publication). The data processing steps were done with the free statistical software R (http://www.r-project.org, R Foundation for Statistical Computing, Vienna, Austria), using an in-house developed script [12]. P-values for expression changes at any of the time points were calculated using a one-way ANOVA statistical analysis.…”

“…In addition, other investigators were able to confirm that a decreased availability of nutrients in B . pertussis cultures after the logarithmic growth phase is associated with a lower expression of many virulence genes in a BvgASR-dependent manner [12, 13]. Taken together, these results strongly suggest that the composition (i.e.…”

“…pertussis [12, 13]. Expression of most virulence genes, whose products are involved in pathogenesis, is controlled by a master regulatory system encoded by the BvgASR locus [14].…”