Raphaël Esson , Stéphanie Falque , Eric Abachin , Steve George , Nolwenn Nougarede
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引用次数: 0
Abstract
To improve pertussis toxin (PT) yield in B. pertussis strains for vaccine production a genetically-engineered strain (gdPT 191-134 strain) with a second copy of the genetically detoxified PT (gdPT) locus was developed. The consistency of the production and genetic stability of the strain when used for vaccine production must be established. We developed two simplex ddPCR assays with PCR systems for ptxA, the target gene present in two copies, and pgm, the reference gene present as a single copy. The ddPCR assay had sufficient precision to discriminate the copy number of the PT locus accurately in two B. pertussis strains: one copy in the parent, non-genetically-engineered strain and two copies in the gdPT 191-134 strain. Using the ddPCR assays, we were able to show that the ratio of the ptxA to pgm genes decreased during serial culture passages, due to the loss of PT locus, which in turn, resulted in lower levels of PT production over time. We were then able to assess culture conditions that improved the stability of the double locus, as shown by non-significant reduction in gdPT toxin yield.
期刊介绍:
Biologicals provides a modern and multidisciplinary international forum for news, debate, and original research on all aspects of biologicals used in human and veterinary medicine. The journal publishes original papers, reviews, and letters relevant to the development, production, quality control, and standardization of biological derived from both novel and established biotechnologies. Special issues are produced to reflect topics of particular international interest and concern.Three types of papers are welcome: original research reports, short papers, and review articles. The journal will also publish comments and letters to the editor, book reviews, meeting reports and information on regulatory issues.