title: 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.
authors.affiliation: Nederlands Vaccin Instituut (NVI), Unit Research and Development, PO Box 457, 3720 AL Bilthoven, The Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: van de Waterbeemd
authors.forename: Mathieu
authors.initials: M
authors.lastname: Streefland
authors.forename: Jeroen
authors.initials: J
authors.lastname: Pennings
authors.forename: Leo
authors.initials: L
authors.lastname: van der Pol
authors.forename: Coen
authors.initials: C
authors.lastname: Beuvery
authors.forename: Johannes
authors.initials: J
authors.lastname: Tramper
authors.forename: Dirk
authors.initials: D
authors.lastname: Martens
mesh_terms: D000942:Antigens, Bacterial / Q000096:biosynthesis*; D001886:Bordetella pertussis / Q000235:genetics / Q000254:growth & development*; D003470:Culture Media / Q000737:chemistry; D020869:Gene Expression Profiling; D018698:Glutamic Acid / Q000032:analysis; D007218:Industrial Microbiology; D019344:Lactic Acid / Q000032:analysis; D010567:Pertussis Vaccine / Q000592:standards*; D011785:Quality Assurance, Health Care; D013997:Time Factors; D037521:Virulence Factors / Q000096:biosynthesis*
chemical_list: D000942:Antigens, Bacterial; D003470:Culture Media; D010567:Pertussis Vaccine; D037521:Virulence Factors; D019344:Lactic Acid; D018698:Glutamic Acid