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Laupheim, Germany

Minow B.,Rentschler Biotechnologie GmBH | De Witt H.,Cellca GmbH | Knabben I.,Rentschler Biotechnologie GmBH
Chemie-Ingenieur-Technik | Year: 2013

A systematic and integrated use of single-use technologies was combined with a robust monoclonal antibody platform, which led to a substantial reduction of manufacturing costs, reduced timelines and increased flexibility in clinical manufacturing. A direct scale-up of a high titer monoclonal antibody-expressing CHO DG44-based cell culture platform was performed from shake flasks to a 1000 L production scale in a completely single-use manufacturing facility. The scale-up was done on the basis of calculating the specific volumetric power input which allowed a direct transfer from small culture volumes to the production scale. The timelines for process development were reduced to 3 months from the Research Cell Bank to the drug substance with highly optimized cells and appropriate culture conditions. Copyright © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Turan S.,Hannover Medical School | Zehe C.,Cellca GmbH | Kuehle J.,Hannover Medical School | Qiao J.,WuXi AppTec | Bode J.,Hannover Medical School
Gene | Year: 2013

Starting in 1991, the advance of Tyr-recombinases Flp and Cre enabled superior strategies for the predictable insertion of transgenes into compatible target sites of mammalian cells. Early approaches suffered from the reversibility of integration routes and the fact that co-introduction of prokaryotic vector parts triggered uncontrolled heterochromatization. Shortcomings of this kind were overcome when Flp-Recombinase Mediated Cassette Exchange entered the field in 1994. RMCE enables enhanced tag-and-exchange strategies by precisely replacing a genomic target cassette by a compatible donor construct. After "gene swapping" the donor cassette is safely locked in, but can nevertheless be re-mobilized in case other compatible donor cassettes are provided ("serial RMCE"). These features considerably expand the options for systematic, stepwise genome modifications. The first decade was dominated by the systematic generation of cell lines for biotechnological purposes. Based on the reproducible expression capacity of the resulting strains, a comprehensive toolbox emerged to serve a multitude of purposes, which constitute the first part of this review. The concept per se did not, however, provide access to high-producer strains able to outcompete industrial multiple-copy cell lines. This fact gave rise to systematic improvements, among these certain accumulative site-specific integration pathways. The exceptional value of RMCE emerged after its entry into the stem cell field, where it started to contribute to the generation of induced pluripotent stem (iPS-) cells and their subsequent differentiation yielding a variety of cell types for diagnostic and therapeutic purposes. This topic firmly relies on the strategies developed in the first decade and can be seen as the major ambition of the present article. In this context an unanticipated, potent property of serial Flp-RMCE setups concerns the potential to re-open loci that have served to establish the iPS status before the site underwent the obligatory silencing process. Other relevant options relate to the introduction of composite Flp-recognition target sites ("heterospecific FRT-doublets"), into the LTRs of lentiviral vectors. These "twin sites" enhance the safety of iPS re-programming and -differentiation as they enable the subsequent quantitative excision of a transgene, leaving behind a single "FRT-twin". Such a strategy combines the established expression potential of the common retro- and lentiviral systems with options to terminate the process at will. The remaining genomic tag serves to identify and characterize the insertion site with the goal to identify genomic "safe harbors" (GOIs) for re-use. This is enabled by the capacity of ". FRT-twins" to accommodate any incoming RMCE-donor cassette with a compatible design. © 2012 Elsevier B.V.

Kober L.,Cellca GmbH | Zehe C.,Cellca GmbH | Bode J.,Hannover Medical School
Biotechnology and Bioengineering | Year: 2012

Most biotherapeutic drugs are recombinant monoclonal antibodies which are mostly produced in monoclonal cell lines derived from Chinese hamster ovary (CHO) cells. Various clones expressing a monoclonal recombinant antibody were analyzed and a correlation of the antibody concentration and the relative mRNA level of calreticulin (CALR), glucose-regulated protein 78 and 94kDa (GRP78, GRP94) and spliced X-box binding protein 1 (XPB1) was observed. By means of these results we were motivated to establish a novel selection system based on endoplasmic reticulum (ER) stress, which allows the rapid identification and isolation of high-expressing clones out of a pool mainly consisting of low- and medium-producing cells. Several ER stress responsive elements were tested with the aid of a recombinase mediated cassette exchange (RMCE) procedure. Very surprisingly, only GRP78 reporter constructs were strongly stimulated upon antibody expression. Furthermore we found that GRP78 reporter constructs are very suitable to reflect the level of antibody expression (IgG) in recombinant CHO cells. Based on these results, it is concluded, that the novel ER stress based selection system developed during this study is suitable to identify and isolate clones with a high level of antibody expression. © 2012 Wiley Periodicals, Inc.

Kober L.,Cellca GmbH | Zehe C.,Cellca GmbH | Bode J.,Hannover Medical School
Biotechnology and Bioengineering | Year: 2013

Recombinant biotherapeutic proteins such as monoclonal antibodies are mostly produced in Chinese hamster ovary (CHO) cells and pharmaceutical companies are interested in an appropriate platform technology for the development of large-scale production processes. A major aim of our study was therefore to improve the secretion efficiency of a recombinant biotherapeutic antibody by optimizing signal peptides. Reporter molecules such as gaussia and vargula luciferase or secreted alkaline phosphatase are frequently used to this end. In striking contrast, we used a biotherapeutic antibody that was fused to 16 different signal peptides during our study. In this way, the secretion efficiency of the recombinant antibody has been analyzed by transient expression experiments in CHO cell lines. Compared to the control signal peptide, it was not possible to achieve higher efficiencies with signal peptides derived from a variety of species or even natural immunoglobulin G signal peptides. The best results were obtained with natural signal peptides derived from human albumin and human azurocidin. These results were confirmed by fed-batch experiments with stably transfected cell pools, in which cell-specific productivities up to 90pgcell-1day-1 and product concentrations up to 4gL-1 could be determined using the albumin signal peptide. Finally, the applicability of the identified signal peptides for both different antibodies and non-antibody products was demonstrated by transient expression experiments. In conclusion, it was found that signal peptides derived from human albumin and human azurocidin are most appropriate to generate cell lines with clearly improved production rates suitable for commercial purposes in a product-independent manner. © 2012 Wiley Periodicals, Inc.

Minow B.,Rentschler Biotechnologie GmBH | Tschoepe S.,Rentschler Biotechnologie GmBH | Regner A.,Rentschler Biotechnologie GmBH | Populin M.,Rentschler Biotechnologie GmBH | And 3 more authors.
Engineering in Life Sciences | Year: 2014

Process transfer is associated with a considerable risk potential. The most critical equipment aspects in upstream operations are the type and scale of bioreactors. Single-use systems have the advantage of a relatively fixed bioreactor design where only few adaptations can be made, e.g. in stirrer geometry or type of submerse aeration. Here, we describe the transfer of a Chinese hamster ovary fed-batch process in the 1000 L scale from a XDR™ to a Thermo Scientific Hyclone Single-Use Bioreactor (S.U.B.) used for GMP compliant manufacturing of biologics. The transfer method, which was based on a preceding intensive characterization of both bioreactors, aimed either to keep the oxygen mass transfer or the power input constant. The transfer strategies were evaluated theoretically based on derived empirical correlations for the mass transfer coefficients, kLaO2 and kLaCO2. An operation boundary of 10-31 W m-3 for the S.U.B. bioreactor was defined, which is an approximately 35 % higher power input compared to that in the XDR™. The transfer strategy succeeded in maintaining essential biological parameters such as cell concentration (±5%), viability (±2%), and product formation (±3%) very similar. This is, to the authors' knowledge, the first time that distinct process performance comparison in different 1000 L SUBs is published. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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