Biomedical Engineering and Bioengineering Commons^™

Identifying Low-Level Sequence Variants Via Next Generation Sequencing To Aid Stable Cho Cell Line Screening, Sheng Zhang, Dean Regier, David Oullette, Ivan Correia, Jerry Carson

Cell Culture Engineering XV

Developing stable Chinese hamster ovary (CHO) cell lines for biotherapeutics is an irreversible process and therefore, key quality attributes, such as sequence variants, must be closely monitored during cell line development (CLD) to avoid delay in the developmental timeline, and more importantly, to assure product safety and efficacy. Sequence variants, defined as unintended amino acid substitution in recombinant protein primary structure, result from alteration at either the DNA or the protein level. Here we report the application of transcriptome sequencing (RNAseq) in an IgG1 monoclonal antibody (mAb) CLD campaign to detect, identify and eliminate cell lines containing low-level point mutations …

Omics Approach For Generating A High-Yield Cho Cell Line Producing Monoclonal Antibodies, Wei Chi, Hsuan-Pu Chen, Dalton Chen, Hsin-Lin Lu, Bor-Shiun Chen, Chao Yi Teng, Chien-I Lin, Hsueh-Lin Lu, Chi-Chen Hsu, Sheng Jie Huang

Cell Culture Engineering XV

Chinese hamster ovary (CHO) cells are extensively used for the industrial manufacture of therapeutic antibodies. Generating high producing cell lines for secretory protein production requires knowing the bottleneck in the cellular machinery for protein expression. Integration site of gene of interest (GOI) is one of the important factors that influence the protein productivity. Even though screening of cells randomly integrated GOI can select high producing cells, the selected cell might not stable due to the chromosome instability. Here, we would like to look for host integration sites where GOI is high yield and stable by screening a single copy integration …

Crispr-Cas9 Knockout Library For Cho, Lasse Ebdrup, Alex Thomas, Hooman Hefzi, Philipp Spahn, Kaen Karottki, Helene Kildegaard, Nathan Lewis

Cell Culture Engineering XV

Traditionally, screening of large CHO cell population have been utilized to identify clones with desired phenotypic properties such as product quality, e.g. specific glyco forms, and population characteristics, e.g. ability to grow in high cell densities.

This has largely depended on the genomic variety naturally present in a large cell population or occasionally utilizing random mutagenesis to increase this variety.

The ability to precisely create genomic variety in mammalian cells have improved dramatically over the past decade and in the past few years the price has dropped substantially due to the CRISPR/Cas9 technology. E.g. knocking out a gene using CRISPR/Cas9 …

Expression Of Glycoproteins With Excellent Pharmacokinetic Properties On The Novel Cap-Go Expression Platform, Silke Wissing

Cell Culture Engineering XV

Due to their clinical importance, the development of therapeutic proteins has accelerated immensely over the past years. However, the expression of highly glycosylated recombinant therapeutic proteins like for example blood coagulation factors or serum proteins, has remained a challenging task.

C1-Inhibitor (C1-Inh) holds 7 N- and 8 O-glycosylation sites. Plasma derived C1-Inh (Berinert) as well as recombinant C1-Inh from transgenic rabbits (Ruconest) are approved for the treatment of acute attacks in patients with hereditary angioedema. However, the recombinant product shows a dramatically reduced serum half-life in pharmacokinetic studies in comparison to the plasma derived counterparts.

We have developed the …

Genetic Engineering Of Cho Cells For Viral Resistance To Mmv: Targeting Virus Binding, Internalization, Intracellular Trafficking And Transport To Nucleus, Joaquina Mascarenhas

Cell Culture Engineering XV

Contamination by the parvovirus Mouse Minute Virus (MMV) remains a challenge in CHO biopharmaceutical production processes. As part of developing a risk mitigation strategy against such events our group has evaluated the genetic engineering of Chinese Hamster Ovary (CHO) cell lines to create a new host cell line that would be resistant to MMV. While the functional receptor for MMV binding to CHO cell surface is unknown, previous work in our group has validated the role of sialic acid on the cell surface as important for cell surface binding and internalization of the MMV virus. In this work we further …

Bispecific Antibodies: Strategies, Considerations And Challenges, Christoph Spiess

Cell Culture Engineering XV

Bispecific antibodies (BsAbs) are moving mainstream as therapeutics with currently two bispecific antibodies approved and about 30 in clinical development. The idea of using a BsAb as a therapeutic has been around for almost as long as its monospecific counterpart, however during this time over 40 MAbs were approved but only two BsAbs. One of the main reasons why BsAbs lag behind is that they are far more complex to produce.

The co-expression of the two different heavy chains and two different light chains results in up to nine unwanted species in addition to the BsAb. Although a BsAb molecule …

Reduction Of Metabolic Waste Products, Ammonia And Lactate, Through The Coupling Of Gs Selection And Ldh-A Down-Regulation In Cho Cells, Soo Min Noh, Jin Hyoung Park, Gyun Min Lee

Cell Culture Engineering XV

The cultivation of Chinese hamster ovary (CHO) cells for the production of therapeutic proteins inevitably accompanies the production of metabolic wastes, mostly ammonia and lactate. Ammonia alters cell growth, productivity and the glycosylation patterns of proteins, and lactate acidifies culture media, having negative effects on cell culture. A stable CHO cell line should be established for the manufacturing process of therapeutic proteins, and the development of stable cell lines is usually based on two expression systems: the dihydrofolate reductase (DHFR) system and the glutamine synthetase (GS) system. Compared to the DHFR system, the GS system produces a reduced level of …

Development Of Hyper Osmotic Resistant Cho Host Cells, Yauharu Kamachi

Cell Culture Engineering XV

We have developed a cell culture platform for monoclonal antibody (IgG) production by Chinese Hamster Ovary (CHO) cells. The platform feed used the continuous feeding method. This platform can maintain high cell density and produce high antibody titer. However because operation of continuous feed is complex, contract manufacturing organization (CMO) that can perform continuous feed is limited. Therefore, we tried to change the feeding method from continuous feed to bolus feed. However the previous studies showed that the rapid changes of osmolality by bolus feed and the hyper osmolality repressed the cell culture growth and the final titer.

In this …

Engineering, Expression Screening, And Production Cell Line Development Of Hetero Ig Molecules Using Charge Pair Mutations, Jennitte Stevens, Guna Kannan, Trent Munro

Cell Culture Engineering XV

In recent years, there has been an increase in therapeutic indications that require bispecific targeting. Bispecific Hetero Ig antibodies that can target two antigens have long been considered as an attractive approach to drive synergistic biologic activity while maintaining the structure and stability of a traditional antibody. However, clinical development of such molecules has been hampered by CMC related challenges relating to product heterogeneity. During the development of a Hetero Ig molecule targeting the Wnt pathway antagonists Dkk-1 and SCL-1, we employed a novel strategy to drive the heterodimerization of IgG antibodies through the addition of charge pair reside mutations …

Predictive Engineering Of Cho Cells Using Systems Biology Models, Nathan Lewis

Cell Culture Engineering XV

Decades of bioprocess optimization have resulted in substantial improvements in recombinant protein production. However, some proteins remain difficult to express, and there is an increasing awareness of the need for improved control of critical quality attributes of recombinant protein drugs. To enable cell engineering efforts to enhance protein production and control product quality, we have enumerated the CHO cell parts through genome sequencing efforts,^1,2 and are now providing context to these parts by reconstructing genome-scale networks of the secretory pathway, glycosylation, and metabolism CHO (Figure 1). Using these models, which account for the activities of more than 2000 genes, …

Process Optimization For Semi-Continuous Virus Production At High Cell Densities, Daniel Vazquez, Michael Pieler, Yvonne Genzel, Ingo Jordan, Volker Sandig, Udo Reichl

Cell Culture Engineering XV

Background. Unlike production of recombinant proteins, continuous production of viral vaccines at high cell densities (HCD) is still constrained by host cell lysis during virus propagation and limited virus recovery from culture broth. Nevertheless, advanced fed-batch [1] and perfusion strategies can be applied to achieve a high-yield virus production processes. In this study, the development of a high-yield semi-continuous process for the production and purification of the modified vaccinia Ankara virus isolate MVA-CR19 and influenza A/PR/8 in HCD cultivations of the suspension cell line AGE1.CR.pIX (ProBioGen AG, Berlin) is presented.

Methods. Depending on the required scale, high cell …

Karyotype-Based Analysis Of Cell Line Instability And Clonality In Cho Cells, Jong Youn Baik, Kelvin Lee

Cell Culture Engineering XV

Chinese hamster ovary (CHO) cell line instability that can result in unexpected changes in phenotypes such as cell growth, productivity, or product quality is challenging for the biomanufacturing of therapeutic proteins. In addition, understanding cell line instability and its relationship to clonality is critical. We hypothesize that chromosomal rearrangements resulting from genomic instability are associated with cell line instability.

We developed cell line instability models using two cell lines: secreted alkaline phosphatase (SEAP)-expressing CHO cells (CHO-SEAP) and their host cells (CHO-DUK). We also developed a karyotype-based framework to quantify chromosomal rearrangements. In the absence of methotrexate (MTX), long-term cultured CHO-SEAP …

Prediction Of Stable And Transient Expression Of Recombinant Proteins From Cho Cells Based Upon Translational Reprogramming, Charlotte Godfrey

Cell Culture Engineering XV

Translational reprogramming and mRNA translation efficiency influence global protein synthesis, cell proliferation and growth; important parameters in defining recombinant protein expression yields. Reprogramming generally results in a down-regulation of overall global protein synthesis. Polysome profiling is used to analyse mRNA translation via the distribution of ribosomes between monosomes and polysomes, and can be used to investigate translational reprogramming occurring within the cell culture. Here this approach has been applied to investigate the endogenous polysome profiles of host and recombinant Chinese Hamster Ovary (CHO) monoclonal antibody-producing cell lines, and how the profiles change across culture depending on the growth and protein …

Establishing A Robust Two-Step Cloning Strategy For The Generation Of Cell Lines With A High Probability Of Monoclonality, Alison Young, Claire Lovelady, Mahesh Shivare, Jarka Glassey, Shirley Coleman, Alison Porter

Cell Culture Engineering XV

A regulatory requirement for the production of therapeutic proteins from mammalian cells is that the production cell line is clonal, that is, derived from a single progenitor cell. It is therefore standard procedure to include at least one cloning step during the development of a recombinant cell line for therapeutic protein production. Numerous techniques can be employed for cloning cell lines, but regardless of the cloning method used there should be appropriate evidence to support that the method is fit for purpose. A point highlighted by the increasing interest from regulatory bodies regarding the cloning method used and the probability …

Identifying Opportunities In Cell Engineering For The Production Of ‘Difficult To Express’ Recombinant Proteins, Hirra Hussain, Alan Dickson, Mark Abbott, Robert Roth, David Fisher

Cell Culture Engineering XV

There is a growing demand for production of recombinant proteins of many structural varieties in mammalian expression systems, either as therapeutics or for protein characterisation. However, certain recombinant proteins are “difficult to express” in mammalian expression systems requiring extensive cell line and process optimisation which, as a result, can have significant consequences for drug development processes. The Tissue Inhibitors of Metalloproteinase (TIMP) protein family, TIMP-2, -3 and -4, are naturally secreted proteins that share significant structural homology (~50% identity and ~70% similarity in amino acid sequence), but show profound differences in secretion in mammalian expression systems. Computational sequence analysis of …

Accelerated Homology-Directed Targeted Integration Of Transgenes In Cho Cells Via Crispr/Cas9 And Fluorescent Enrichment, Jae Seong Lee, Lise Marie Grav, Gyun Min Lee, Helene Kildegaard

Cell Culture Engineering XV

Development of recombinant CHO cell lines has been hampered by unstable and variable transgene expression caused by random integration. With draft genome of several CHO cell lines and targeted genome editing technologies, rCHO cell line development based on site-specific integration has the potential to overcome the limitations of clonal heterogeneity. In a previous study, we demonstrated efficient and precise targeted gene integration in CHO cells using CRISPR/Cas9 technology and homology-directed repair (HDR) pathway¹⁾. However, it requires a selection process, which limits targeted integration of multiple transgenes at multiple sites due to a limited number of selection markers and …

Pilot Study To Assess Breathing During Sight-Read Stringed Instrument Performance, Collin T. Erickson, Clark Potter, Gregory Bashford

UCARE: Research Products

For many musicians, one common occurrence during a performance is the presence of stage fright. Stage fright, though not always expressed can influence the confidence and self-esteem of a performer, and thus can affect the quality of the performance. Every day musicians are affected by stage fright, and there has been no exact solution as to how to lessen the feeling of anxiety musicians feel before performing. No data has been collected to find the correlation between the regularity of breathing and the level of stage fright that a person feels during their performance. A way to quantify regularity of …

Proof That Can Travel - Documented Clonality Report For Regulatory Submission, Ian Taylor, Paul Miller

Cell Culture Engineering XV

Clonality is a key element of cell line development and is an important component of a regulatory submission. Indeed for BLA, the clonality of MCB is mandatory. Historically, the regulator has insisted upon 2 rounds of cloning for developing a cell line and assurance of monoclonality based on statistical outgrowth measurements. Recent improvements in high resolution whole well imaging of cells in microplates, enables the creation of indisputable image-based evidence for the growth of a colony from a single cell. This evidence eliminates a round of sub-cloning and results in several months of cell line development time being saved. However, …

An Integrated Cell Line Development Platform For Generation Of High Yielding Cho Stable Cell Lines Expressing A Stabilized Trimeric Pre-Fusion Rsv F Recombinant Viral Glycoprotein, Richard Schwartz, Amritha Menon, Mingzhong Chen, Giulia Fabozzi, Althaf Hussain

Cell Culture Engineering XV

Accelerating timelines to deliver stable cell lines with high productivity is challenging, especially for biologics portfolios which include complex recombinant vaccine constructs. The VRC’s current integrated approach to shorten CHO cell line development timeline utilizes host cells pre-adapted to production medium, optimization of the expression vectors, improved pre and post-transfection methodology, automated ClonePix^TM technology and top clone selection and ranking in micro-scale ambr bioreactor technology. This platform was developed with monoclonal antibodies as model proteins. While this integrated platform enabled generation of high yielding clones expressing monoclonal antibodies, it was initially much less successful with a difficult to express …

Overcoming Process Intensification Challenges To Deliver A Manufacturable And Competitive Integrated Continuous Biomanufacturing Platform, Jason Walther, Neha Shah, Myles Hollenbach, Jonathan Wang, Marcella Yu, Jiuyi Lu, Yang Yang, Konstantin Konstantinov, Chris Hwang

Cell Culture Engineering XV

Groups in both industry and academia have achieved high densities and productivities in perfusion cell culture processes. At Sanofi, we have demonstrated perfusion densities greater than 100 million cells/mL (with associated high productivities) at a cell-specific perfusion rate of only 20 pL/cell/day. This process intensification reduces the footprint of upstream unit operations as well as capital and operating expenses of manufacturing facilities. The continuous nature of perfusion cell culture also creates opportunities for integration of continuous downstream operations, leading to further process intensifications and volume reductions.

In this presentation, we will discuss our work on several upstream challenges that must …