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Appl. Environ. Microbiol., Jan 1997, 122-127, Vol 63, No. 1
A Suarez, LH Staendner, M Rohde, G Piatti, KN Timmis and CA Guzman
Pertussis toxin (PT) is an essential component of accellular vaccines
against whooping cough. However, the industrial production of PT from
Bordetella pertussis is impaired by slow growth and poor yields. To
overcome these problems, we have constructed a minitransposon containing
the tox operon under the control of a tightly regulated promoter responsive
to an aromatic inducer. The expression cassettes have been integrated into
the chromosome of Bordetella bronchiseptica 5376 and ATCC 10580 bvg. Five
recombinant clones containing the tox operon under the control of the Psal
promoter, which is activated by the product of nahR, were further
characterized. The recombinant clones expressed PT after only 3 h of
induction with sodium salicylate at levels similar to those of B. pertussis
grown for 24 h. The stability of the engineered phenotype was 100% after 72
h of growth without selective pressure. The growth pattern was not modified
either under noninducing conditions or in the presence of the inducer at
low concentrations, suggesting that strain performance would not be
affected in bioreactors when uncoupled from gene expression. Recombinant
PT, which was localized mainly in the periplasm, was purified by affinity
chromatography. The recombinant protein was immunologically
indistinguishable from wild-type PT and retained its biological activity as
determined by the CHO cell-clustering test. These recombinant clones appear
to be useful tools for the cost- effective production of PT under
conditions of improved biosafety, as demonstrated by the inducible
expression of PT uncoupled from the bacterial biomass in a nonvirulent and
fast-growing B. bronchiseptica background.
Copyright © 1997, American Society for Microbiology
Stable expression of pertussis toxin in Bordetella bronchiseptica under the control of a tightly regulated promoter
Division of Microbiology, GBF-National Research Centre for Biotechnology, Braunschweig, Germany.
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