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Danielewicz N, Dai W, Rosato F, Webb ME, Striedner G, Römer W, Turnbull WB, Mairhofer J. In-Depth Characterization of a Re-Engineered Cholera Toxin Manufacturing Process Using Growth-Decoupled Production in Escherichia coli. Toxins (Basel) 2022; 14:396. [PMID: 35737057 PMCID: PMC9228256 DOI: 10.3390/toxins14060396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/24/2022] [Accepted: 05/31/2022] [Indexed: 12/10/2022] Open
Abstract
Non-toxic derivatives of the cholera toxin are extensively used in neuroscience, as neuronal tracers to reveal the location of cells in the central nervous system. They are, also, being developed as vaccine components and drug-delivery vehicles. Production of cholera-toxin derivatives is often non-reproducible; the quality and quantity require extensive fine-tuning to produce them in lab-scale settings. In our studies, we seek a resolution to this problem, by expanding the molecular toolbox of the Escherichia coli expression system with suitable production, purification, and offline analytics, to critically assess the quality of a probe or drug delivery, based on a non-toxic derivative of the cholera toxin. We present a re-engineered Cholera Toxin Complex (rCTC), wherein its toxic A1 domain was replaced with Maltose Binding Protein (MBP), as a model for an rCTC-based targeted-delivery vehicle. Here, we were able to improve the rCTC production by 11-fold (168 mg/L vs. 15 mg/L), in comparison to a host/vector combination that has been previously used (BL21(DE3) pTRBAB5-G1S). This 11-fold increase in the rCTC production capability was achieved by (1) substantial vector backbone modifications, (2) using Escherichia coli strains capable of growth-decoupling (V strains), (3) implementing a well-tuned fed-batch production protocol at a 1 L scale, and (4) testing the stability of the purified product. By an in-depth characterization of the production process, we revealed that secretion of rCTC across the E. coli Outer Membrane (OM) is processed by the Type II secretion-system general secretory pathway (gsp-operon) and that cholera toxin B-pentamerization is, likely, the rate-limiting step in complex formation. Upon successful manufacturing, we have validated the biological activity of rCTC, by measuring its binding affinity to its carbohydrate receptor GM1 oligosaccharide (Kd = 40 nM), or binding to Jurkat cells (93 pM) and delivering the cargo (MBP) in a retrograde fashion to the cell.
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Affiliation(s)
- Natalia Danielewicz
- enGenes Biotech GmbH, Mooslackengasse 17, 1190 Vienna, Austria;
- Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria;
| | - Wenyue Dai
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (W.D.); (M.E.W.); (W.B.T.)
| | - Francesca Rosato
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany; (F.R.); (W.R.)
- Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
| | - Michael E. Webb
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (W.D.); (M.E.W.); (W.B.T.)
| | - Gerald Striedner
- Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria;
| | - Winfried Römer
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany; (F.R.); (W.R.)
- Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, 79104 Freiburg, Germany
| | - W. Bruce Turnbull
- School of Chemistry and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK; (W.D.); (M.E.W.); (W.B.T.)
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Food-grade expression of nattokinase in Lactobacillus delbrueckii subsp. bulgaricus and its thrombolytic activity in vitro. Biotechnol Lett 2020; 42:2179-2187. [PMID: 32705453 DOI: 10.1007/s10529-020-02974-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVES To produce nattokinase in a food-grade expression system and evaluate its thrombolytic activity in vitro. RESULTS No nattokinase activity from reconstituted strains was observed in simulated gastric juice, but the enzyme was stable in intestinal fluid, the relative activity of which was found to be 60% after 4 h. Due to the nattokinase being produced intracellularly by recombinant bacterial strains, the persistence of the bacteria in gastric juice ensured transmission of the nattokinase into intestinal juice. Because of subsequent disintegration of the bacteria, the highest nattokinase activity was observed after 3 h at approximately 32%, following its carriage within the recombinant strains to the intestinal fluid. CONCLUSIONS This study demonstrated that nattokinase from recombinant strains exhibited good thrombolytic activity in vitro and may be used by the dairy fermentation industry for the development of novel thrombolytic functional foods.
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pUC18-CpG Is an Effective Adjuvant for a Duck Tembusu Virus Inactivated Vaccine. Viruses 2020; 12:v12020238. [PMID: 32093377 PMCID: PMC7077240 DOI: 10.3390/v12020238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/06/2020] [Accepted: 02/12/2020] [Indexed: 12/16/2022] Open
Abstract
Duck Tembusu virus (DTMUV) is an emerging pathogenic flavivirus responsible for massive economic losses in the duck industry. However, commercially inactivated DTMUV vaccines have been ineffective at inducing protective immunity in ducks. The widely used adjuvant cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs) reportedly improve humoral and cellular immunities in animal models. However, its effectiveness in DTMUV vaccines requires validation. Here, we assessed the protective efficacy of pUC18-CpG as an adjuvant in an inactivated live DTMUV vaccine in ducks. Our results revealed that the serum hemagglutination inhibition (HI) antibody titers, positive rates of anti-DTMUV antibodies, the concentration of serum cytokines, and protection efficacy were significantly increased in ducks immunized with pUC18-CpG compared to that in the control group. Moreover, ducks immunized with a full vaccine dose containing a half dose of antigen supplemented with 40 μg of pUC18-CpG exhibited the most potent responses. This study suggests that pUC18-CpG is a promising adjuvant against DTMUV, which might prove effective in treating other viral diseases in waterfowl.
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