Bioreactor productivity and media cost comparison for different intensified cell culture processes

Enhancing monoclonal antibody production efficiency using CHO-MK cells and specific media in a conventional fed-batch culture

Chinese hamster ovary (CHO) cell lines, derived as subclones from the original CHO cell line, are widely used hosts for current biopharmaceutical productions. Recently, a highly proliferative host cell line, CHO-MK, was established from the Chinese hamster ovary tissue. In this study, we assessed the fundamental culture characteristics and capabilities of CHO-MK cells for monoclonal antibody (mAb) production using specified chemically defined media. To achieve this, we established fed-batch cultures of model CHO-MK cells in shake flasks and ambr15 and 2 L bioreactors under various conditions. The mAb-producing CHO-MK cell line A produced 12.6 g/L of antibody within 7 days in the fed-batch culture using a 2 L bioreactor, with a seeding density of 1 × 106 cells/mL. This performance corresponded to a space-time yield of 1.80 g/L/day, representing a productivity level that could be challengingly attained in fed-batch cultures using conventional CHO cells. In addition, when we subjected six different mAb-producing CHO-MK cell lines to fed-batch culture in the ambr15 bioreactor for 7 days, the antibody production ranged between 5.1 and 10.8 g/L, confirming that combining CHO-MK cells and specified media leads to enhanced versatility. These discoveries underscore that CHO-MK cells combined with specified media might represent a next-generation production platform, which could potentially respond to an increasing demand for antibody drugs, reducing production costs, and shortening antibody drug development times. This study is expected to serve as a benchmark for future production process development using CHO-MK cells.

Regeneration of Spent Culture Media for Sustainable and Continuous mAb Production via Ion Concentration Polarization

In modern bioprocessing, cell culture media is one of the most significant cost drivers, yet the nutrients and other critical factors in the media are often not fully utilized. With the renewed emphasis on reducing the cost of bioprocessing, there is much interest in reducing the overall use of cell culture media. In this work, we introduce a mesoscale microfluidic separation device based on the ion concentration polarization (ICP) process to regenerate the spent media for reuse by removing critical waste products from the cell culture that are known to inhibit the growth of the cells. We demonstrated that up to 75% of spent culture media can be regenerated and reused without affecting the cell viability. A detailed analysis of the materials consumed during antibody production indicated that one could improve the water process mass intensity by up to 33% by regenerating and recycling the media. Given that ICP separation systems have already been scaled up to support large-volume processing, it would be feasible to deploy this technology for manufacturing scale bioreactors (e.g., 50 L perfusion culture of CHO cells), reducing the overall operation cost and water use.

A comparison of different intensified upstream processes highlighting the advantage of WuXi Biologics' Ultra-high Productivity platform (WuXiUPTM) in improved product quality and purification yield

WuXiUPTM, WuXi Biologics' Ultra-high Productivity platform, is an intensified and integrated continuous bioprocess platform developed for production of various biologics including monoclonal antibodies, fusion proteins, and bispecific antibodies. This process technology platform has manifested its remarkable capability in boosting the volumetric productivity of various biologics and has been implemented for large-scale clinical material productions. In this paper, case studies of the production of different pharmaceutical proteins using two high-producing and intensified culture modes of WuXiUPTM and the concentrated fed-batch (CFB), as well as the traditional fed-batch (TFB) are discussed from the perspectives of cell growth, productivity, and protein quality. Both WuXiUPTM and CFB outperformed TFB regarding volumetric productivity. Additionally, distinctive advantages in product quality profiles in the WuXiUPTM process, such as reduced acidic charge variants and fragmentation, are revealed. Therefore, a simplified downstream purification process with only two chromatographic steps can be developed to deliver the target product at a satisfactory purity and an extremely-high yield.

Fed-batch strategies for intensified rVSV vector production in high cell density cultures of suspension HEK293 cells

Vesicular stomatitis virus (VSV) has been increasingly demonstrated as a promising viral vector platform. As the interest over this modality for vaccine and gene therapy applications increases, the need for intensified processes to produce these vectors emerge. In this study, we develop fed-batch-based operations to intensify the production of a recombinant VSV-based vaccine candidate (rVSV-SARS-CoV-2) in suspension cultures of HEK293 cells. A feeding strategy, in which a commercial concentrated medium was added to cultures based on cell growth through a fixed cell specific feeding rate (CSFR), was applied for the development of two different processes using Ambr250 modular bioreactors. Cultures operated in hybrid fed-batch/perfusion (FB/P) or fed-batch (FB) were able to sustain infections performed at 8.0 × 106 cells/mL, respectively resulting in 3.9 and 5.0-fold increase in total yield (YT) and 1.7 and 5.6-fold increase in volumetric productivity (VP) when compared with a batch reference. A maximum viral titer of 4.5 × 1010 TCID50/mL was reached, which is comparable or higher than other processes for VSV production in different cell lines. Overall, our study reports efficient fed-batch options to intensify the production of a rVSV-based vaccine candidate in suspension HEK293 cells.

Continuous catalytic production of 1,3-dihydroxyacetone: Sustainable approach combining perfusion cultures and immobilized cells

Currently, the predominant method for the industrial production of 1,3-dihydroxyacetone (DHA) from glycerol involves fed-batch fermentation. However, previous research has revealed that in the biocatalytic synthesis of DHA from glycerol, when the DHA concentration exceeded 50 g·L-1, it significantly inhibited microbial growth and metabolism, posing a challenge in maintaining prolonged and efficient catalytic production of DHA. In this study, a new integrated continuous production and synchronous separation (ICSS) system was constructed using hollow fiber columns and perfusion culture technology. Additionally, a cell reactivation technique was implemented to extend the biocatalytic ability of cells. Compared with fed-batch fermentation, the ICSS system operated for 360 h, yielding a total DHA of 1237.8 ± 15.8 g. The glycerol conversion rate reached 97.7 %, with a productivity of 3.44 g·L-1·h-1, representing 485.0 % increase in DHA production. ICSS system exhibited strong operational characteristics and excellent performance, indicating significant potential for applications in industrial bioprocesses.

Platform development for high-throughput optimization of perfusion processes: Part I: Implementation of cell bleeds in microwell plates

The promise of continuous processing to increase yields and improve product quality of biopharmaceuticals while decreasing the manufacturing footprint is transformative. Developing and optimizing perfusion operations requires screening various parameters, which is expensive and time-consuming when using benchtop bioreactors. Scale-down models (SDMs) are the most feasible option for high-throughput data generation and condition screening. However, new SDMs mimicking perfusion are required, enabling experiments to be run in parallel. In this study, a method using microwell plates (MWP) operating in semi-perfusion mode with an implemented cell bleed step is presented. A CHO cell line was cultivated in a 24-well MWP (Vw = 1.2 mL) and grown at four high cell density (HCD) setpoints. Quasi steady-state condition was obtained by manually performing cell bleeds followed by a total medium exchange after centrifugation. Further, two HCD setpoints were scaled up (VW = 30 mL), comparing a squared six-well deepwell plate (DWP) to shake flasks (SF). This evaluation showed comparable results between systems (DWP vs. SF) and scales (MWP vs. DWP + SF). The results show that the well-plate-based methods are suitable to perform HCD and quasi steady-state cultivations providing a robust solution to industrially relevant challenges such as cell clone and media selection.

Chromatography affinity resin with photosynthetically-sourced protein A ligand

Green, photosynthesizing plants can be proficiently used as cost-effective, single-use, fully biodegradable bioreactors for environmentally-friendly production of a variety of valuable recombinant proteins. Being near-infinitely scalable and most energy-efficient in generating biomass, plants represent profoundly valid alternatives to conventionally used stationary fermenters. To validate this, we produced a plastome-engineered tobacco bioreactor line expressing a recombinant variant of the protein A from Staphylococcus aureus, an affinity ligand widely useful in antibody purification processes, reaching accumulation levels up to ~ 250 mg per 1 kg of fresh leaf biomass. Chromatography resin manufactured from photosynthetically-sourced recombinant protein A ligand conjugated to agarose beads demonstrated the innate pH-driven ability to bind and elute IgG-type antibodies and allowed one-step efficient purification of functional monoclonal antibodies from the supernatants of the producing hybridomas. The results of this study emphasize the versatility of plant-based recombinant protein production and illustrate its vast potential in reducing the cost of diverse biotechnological applications, particularly the downstream processing and purification of monoclonal antibodies.

Developing an ultra-intensified fed-batch cell culture process with greatly improved performance and productivity

Intensified fed-batch (IFB), a popular cell culture intensification strategy, has been widely used for productivity improvement through high density inoculation followed by fed-batch cultivation. However, such an intensification strategy may counterproductively induce rapidly progressing cell apoptosis and difficult-to-sustain productivity. To improve culture performance, we developed a novel cell culture process intermittent-perfusion fed-batch (IPFB) which incorporates one single or multiple cycles of intermittent perfusion during an IFB process for better sustained cellular and metabolic behaviors and notably improved productivity. Unlike continuous perfusion or other semi-continuous processes such as hybrid perfusion fed-batch with only early-stage perfusion, IPFB applies limited times of intermittent perfusion in the mid-to-late stage of production and still inherits bolus feedings on nonperfusion days as in a fed-batch culture. Compared to IFB, an average titer increase of ~45% was obtained in eight recombinant CHO cell lines studied. Beyond IPFB, ultra-intensified IPFB (UI-IPFB) was designed with a markedly elevated seeding density of 20-80 × 106 cell/mL, achieved through the conventional alternating tangential flow filtration (ATF) perfusion expansion followed with a cell culture concentration step using the same ATF system. With UI-IPFB, up to ~6 folds of traditional fed-batch and ~3 folds of IFB productivity were achieved. Furthermore, the application grounded in these two novel processes showed broad-based feasibility in multiple cell lines and products of interest, and was proven to be effective in cost of goods reduction and readily scalable to a larger scale in existing facilities.

Intensified Influenza Virus Production in Suspension HEK293SF Cell Cultures Operated in Fed-Batch or Perfusion with Continuous Harvest

Major efforts in the intensification of cell culture-based viral vaccine manufacturing focus on the development of high-cell-density (HCD) processes, often operated in perfusion. While perfusion operations allow for higher viable cell densities and volumetric productivities, the high perfusion rates (PR) normally adopted-typically between 2 and 4 vessel volumes per day (VVD)-dramatically increase media consumption, resulting in a higher burden on the cell retention device and raising challenges for the handling and disposal of high volumes of media. In this study, we explore high inoculum fed-batch (HIFB) and low-PR perfusion operations to intensify a cell culture-based process for influenza virus production while minimizing media consumption. To reduce product retention time in the bioreactor, produced viral particles were continuously harvested using a tangential flow depth filtration (TFDF) system as a cell retention device and harvest unit. The feeding strategies developed-a hybrid fed-batch with continuous harvest and a low-PR perfusion-allowed for infections in the range of 8-10 × 106 cells/mL while maintaining cell-specific productivity comparable to the batch control, resulting in a global increase in the process productivity. Overall, our work demonstrates that feeding strategies that minimize media consumption are suitable for large-scale influenza vaccine production.

Risk assessment for biopharmaceutical single-use manufacturing: A case study of upstream continuous processing

In the current transition to intensified upstream processing, the risks of adopting traditional single-use systems for high-titer, long-duration perfusion cultures, have thus far not been considered. This case study uses the Failure Modes and Effects Analysis (FMEA) method to evaluate the risks associated with implementing upstream single-use technology. The simulated model process was used to compare the risk level of single-use technology for a traditional fed-batch cell culture with that for perfusion culture, under the same annual protein production conditions. To provide a reasonable source of potential risk for FMEA, all single-use upstream operations for both fed-batch and perfusion processes were investigated using an analytical method developed to quantify the impact of process parameters and operating conditions on single-use system specifications and to ensure objectivity. Many of the risks and their levels, were similar in long-duration perfusion cultures and fed-batch cultures. However, differences were observed for high-risk components such as daily sampling and installation. The result of this analysis indicates that the reasons for risk are different for fed-batch cultures and perfusion cultures such as larger bioreactors in fed-batch and longer runs in perfusion, respectively. This risk assessment method could identify additional control measures and be part of a holistic contamination control strategy and help visualize their effectiveness.

Modulating antibody effector functions by Fc glycoengineering

Antibody based drugs, including IgG monoclonal antibodies, are an expanding class of therapeutics widely employed to treat cancer, autoimmune and infectious diseases. IgG antibodies have a conserved N-glycosylation site at Asn297 that bears complex type N-glycans which, along with other less conserved N- and O-glycosylation sites, fine-tune effector functions, complement activation, and half-life of antibodies. Fucosylation, galactosylation, sialylation, bisection and mannosylation all generate glycoforms that interact in a specific manner with different cellular antibody receptors and are linked to a distinct functional profile. Antibodies, including those employed in clinical settings, are generated with a mixture of glycoforms attached to them, which has an impact on their efficacy, stability and effector functions. It is therefore of great interest to produce antibodies containing only tailored glycoforms with specific effects associated with them. To this end, several antibody engineering strategies have been developed, including the usage of engineered mammalian cell lines, in vitro and in vivo glycoengineering.

Modulating and optimizing Pluronic F-68 concentrations and feeding for intensified perfusion Chinese hamster ovary cell cultures

Perfusion culture is often performed with micro-sparger to fulfill the high oxygen demand from the densified cells. Protective additive Pluronic F-68 (PF-68) is widely used to mitigate the adverse effect in cell viability from micro-sparging. In this study, different PF-68 retention ratio in alternating tangential filtration (ATF) columns was found to be crucial for cell performance of different perfusion culture modes. The PF-68 in the perfusion medium was found retained inside the bioreactor when exchanged through ATF hollow fibers with a small pore size (50 kD). The accumulated PF-68 could provide sufficient protection for cells under micro-sparging. On the other hand, with large-pore-size (0.2 μm) hollow fibers, PF-68 could pass through the ATF filtration membranes with little retention, and consequently led to compromised cell growth. To overcome the defect, a PF-68 feeding strategy was designed and successfully verified on promoting cell growth with different Chinese hamster ovary (CHO) cell lines. With PF-68 feeding, enhancements were observed in both viable cell densities (20%-30%) and productivity (~30%). A threshold PF-68 concentration of 5 g/L for high-density cell culture (up to 100 × 106  cells/mL) was also proposed and verified. The additional PF-68 feeding was not observed to affect product qualities. By designing the PF-68 concentration of perfusion medium to or higher than the threshold level, a similar cell growth enhancement was also achieved. This study systematically investigated the protecting role of PF-68 in intensified CHO cell cultures, shedding a light on the optimization of perfusion cultures through the control of protective additives.

A novel hybrid bioprocess strategy addressing key challenges of advanced biomanufacturing

Monoclonal antibodies (mAb) are commonly manufactured by either discontinuous operations like fed-batch (FB) or continuous processes such as steady-state perfusion. Both process types comprise opposing advantages and disadvantages in areas such as plant utilization, feasible cell densities, media consumption and process monitoring effort. In this study, we show feasibility of a promising novel hybrid process strategy that combines beneficial attributes of both process formats. In detail, our strategy comprises a short duration FB, followed by a fast media exchange and cell density readjustment, marking the start of the next FB cycle. Utilizing a small-scale screening tool, we were able to identify beneficial process parameters, including FB interval duration and reinoculation cell density, that allow for multiple cycles of the outlined process in a reproducible manner. In addition, we could demonstrate scalability of the process to a 5L benchtop system, using a fluidized-bed centrifuge as scalable media exchange system. The novel process showed increased productivity (+217%) as well as longer cultivation duration, in comparison to a standard FB with a significantly lower media consumption per produced product (-50%) and a decreased need for process monitoring, in comparison to a perfusion cultivation. Further, the process revealed constant glycosylation pattern in comparison to the perfusion cultivation and has strong potential for further scale-up, due to the use of fully scalable cultivation and media exchange platforms. In summary, we have developed a novel hybrid process strategy that tackles the key challenges of current biomanufacturing of either low productivity or high media consumption, representing a new and innovative approach for future process intensification efforts.

Rapid Identification of Chinese Hamster Ovary Cell Apoptosis and Its Potential Role in Process Robustness Assessment

Currently, the assessment of process robustness is often time-consuming, labor-intensive, and material-intensive using process characterization studies. Therefore, a simple and time-saving method is highly needed for the biopharmaceutical industry. Apoptosis is responsible for 80% of Chinese hamster ovary (CHO) cell deaths and affects the robustness of the cell culture process. This study’s results showed that a more robust process can support cells to tolerate apoptosis for a longer time, suggesting that the robustness of the process could be judged by the ability of cells to resist apoptosis. Therefore, it is necessary to establish a rapid method to detect the apoptosis of CHO cells. In trying to establish a new method for detecting apoptosis in large-scale cell cultures, glucose withdrawal was studied, and the results showed that CHO cells began to apoptose after glucose was consumed. Then, the concentration of extracellular potassium increased, and a prolongation of apoptosis time was observed. Further study results showed that the process with poor robustness was associated with a higher proportion of apoptosis and extracellular potassium concentration, so potassium could be used as a biochemical index of apoptosis. The strategy we present may be used to expedite the assessment of process robustness to obtain a robust cell culture process for other biologics.

Upstream continuous processing: recent advances in production of biopharmaceuticals and challenges in manufacturing

Upstream continuous processing, or most commonly perfusion processing, for biopharmaceutical production, is emerging as a feasible and viable manufacturing approach. Development in production of recombinant therapeutic proteins as well as viral vectors, vaccines, and cell therapy products, has numerous research publications that came out in previous years. Recent research areas are in perfusion-operation strategies maximizing and controlling bioreactor cell density, adding feed solution designed to supplement basal medium feed stream, combining cell line engineering with bioreactor conditions such as hypoxia, and implementing online process monitoring of cell density by capacitance sensor and metabolites by Raman spectroscopy. Perfusion applications are not limited to production process alone but include other upstream areas where high cell density process is essential such as in cell bank preparation, N-1 seed bioreactor, and combination with intensified fed-batch production process. This review covers recent advances in continuous processing over the last two years for biopharmaceutical production.

Plant-produced recombinant cytokines IL-37b and IL-38 modulate inflammatory response from stimulated human PBMCs

Affordable therapeutics are vitally needed for humans worldwide. Plant-based production of recombinant proteins can potentially enhance, back-up, or even substitute for the manufacturing capacity of the conventional, fermenter-based technologies. We plastome-engineered a tobacco cultivar to express high levels of two "plantakines" - recombinant human cytokines, interleukins IL-37b and IL-38, and confirmed their native conformation and folding. Assessment of their biological functionality was performed ex vivo by analyzing the effects exerted by the plantakines on levels of 11 cytokines secreted from human peripheral blood mononuclear cells (PBMCs) challenged with an inflammatory agent. Application of the plant-produced IL-37b and IL-38 in PBMCs stimulated with Lipopolysaccharide or Phytohaemagglutinin resulted in significant, and in particular cases-dose-dependent modulation of pro-inflammatory cytokines secretion, showing attenuation in two-thirds of significant level modulations observed. Plantakine treatments that increased inflammatory responses were associated with the higher dosage. Our results demonstrate feasibility of manufacturing functional recombinant human proteins using scalable, cost-effective and eco-friendly plant-based bioreactors.

Expansion and differentiation of ex vivo cultured erythroblasts in scalable stirred bioreactors

Transfusion of donor-derived red blood cells (RBCs) is the most common form of cell therapy. Production of transfusion-ready cultured RBCs (cRBCs) is a promising replacement for the current, fully donor-dependent therapy. A single transfusion unit, however, contains 2 × 10¹² RBC, which requires large scale production. Here, we report on the scale-up of cRBC production from static cultures of erythroblasts to 3 L stirred tank bioreactors, and identify the effect of operating conditions on the efficiency of the process. Oxygen requirement of proliferating erythroblasts (0.55-2.01 pg/cell/h) required sparging of air to maintain the dissolved oxygen concentration at the tested setpoint (2.88 mg O₂ /L). Erythroblasts could be cultured at dissolved oxygen concentrations as low as 0.7 O₂ mg/ml without negative impact on proliferation, viability or differentiation dynamics. Stirring speeds of up to 600 rpm supported erythroblast proliferation, while 1800 rpm led to a transient halt in growth and accelerated differentiation followed by a recovery after 5 days of culture. Erythroblasts differentiated in bioreactors, with final enucleation levels and hemoglobin content similar to parallel cultures under static conditions.

Continuous manufacturing of monoclonal antibodies: Automated downstream control strategy for dynamic handling of titer variations

Handling long-term dynamic variability in harvest titer is a critical challenge in continuous downstream manufacturing. This challenge is becoming increasingly important with the advent of high-titer clones and modern upstream perfusion processes where the titer can vary significantly across the course of a campaign. In this paper, we present a strategy for real-time, dynamic adjustment of the entire downstream train, including capture chromatography, viral inactivation, depth filtration, polishing chromatography, and single-pass formulation, to accommodate variations in titer from 1-7 g/L. The strategy was tested in real time in a continuous downstream purification process of 36 h duration with induced titer variations. The dynamic control strategy leverages real-time NIR-based concentration sensors in the harvest material to continuously track the titer, integrated with an in-house Python-based control system that operates a BioSMB for carrying out capture and polishing chromatography, as well as a series of pumps and solenoid valves for carrying out viral inactivation and formulation. A set of 9 different methods, corresponding to the different harvest titers have been coded onto the Python controller. The methods have a varying number of chromatography columns (3-6 for Protein A and 2-10 for CEX), designed to ensure proper scheduling and optimize productivity across the entire titer variation space. The approach allows for a wide range of titers to be processed on a single integrated setup without having to change equipment or to re-design each time. The strategy also overcomes a key unexplored challenge in continuous processing, namely hand-shaking the downstream train to upstream conditions with long-term titer variability while maintaining automated operation with high productivity and robustness.

Dextran sulfate prevents excess aggregation of human pluripotent stem cells in 3D culture by inhibiting ICAM1 expression coupled with down-regulating E-cadherin through activating the Wnt signaling pathway

Background

Human pluripotent stem cells (hPSCs) have great potential in applications for regenerative medicine and drug development. However, 3D suspension culture systems for clinical-grade hPSC large-scale production have been a major challenge. Accumulating evidence has demonstrated that the addition of dextran sulfate (DS) could prevent excessive adhesion of hPSCs from forming larger aggregates in 3D suspension culture. However, the signaling and molecular mechanisms underlying this phenomenon remain elusive.

Methods

By using a cell aggregate culture assay and separating big and small aggregates in suspension culture systems, the potential mechanism and downstream target genes of DS were investigated by mRNA sequence analysis, qRT-PCR validation, colony formation assay, and interference assay.

Results

Since cellular adhesion molecules (CAMs) play important roles in hPSC adhesion and aggregation, we assumed that DS might prevent excess adhesion through affecting the expression of CAMs in hPSCs. As expected, after DS treatment, we found that the expression of CAMs was significantly down-regulated, especially E-cadherin (E-cad) and intercellular adhesion molecule 1 (ICAM1), two highly expressed CAMs in hPSCs. The role of E-cad in the adhesion of hPSCs has been widely investigated, but the function of ICAM1 in hPSCs is hardly understood. In the present study, we demonstrated that ICAM1 exhibited the capacity to promote the adhesion in hPSCs, and this adhesion was suppressed by the treatment with DS. Furthermore, transcriptomic analysis of RNA-seq revealed that DS treatment up-regulated genes related to Wnt signaling resulting in the activation of Wnt signaling in which SLUG, TWIST, and MMP3/7 were highly expressed, and further inhibited the expression of E-cad.

Conclusion

Our results demonstrated that DS played an important role in controlling the size of hPSC aggregates in 3D suspension culture by inhibiting the expression of ICAM1 coupled with the down-regulation of E-cad through the activation of the Wnt signaling pathway. These results represent a significant step toward developing the expansion of hPSCs under 3D suspension condition in large-scale cultures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02890-4.

N-1 Perfusion Platform Development Using a Capacitance Probe for Biomanufacturing

Fed-batch process intensification with a significantly shorter culture duration or higher titer for monoclonal antibody (mAb) production by Chinese hamster ovary (CHO) cells can be achieved by implementing perfusion operation at the N-1 stage for biomanufacturing. N-1 perfusion seed with much higher final viable cell density (VCD) than a conventional N-1 batch seed can be used to significantly increase the inoculation VCD for the subsequent fed-batch production (referred as N stage), which results in a shorter cell growth phase, higher peak VCD, or higher titer. In this report, we incorporated a process analytical technology (PAT) tool into our N-1 perfusion platform, using an in-line capacitance probe to automatically adjust the perfusion rate based on real-time VCD measurements. The capacitance measurements correlated linearly with the offline VCD at all cell densities tested (i.e., up to 130 × 10⁶ cells/mL). Online control of the perfusion rate via the cell-specific perfusion rate (CSPR) decreased media usage by approximately 25% when compared with a platform volume-specific perfusion rate approach and did not lead to any detrimental effects on cell growth. This PAT tool was applied to six mAbs, and a platform CSPR of 0.04 nL/cell/day was selected, which enabled rapid growth and maintenance of high viabilities for four of six cell lines. In addition, small-scale capacitance data were used in the scaling-up of N-1 perfusion processes in the pilot plant and in the GMP manufacturing suite. Implementing a platform approach based on capacitance measurements to control perfusion rates led to efficient process development of perfusion N-1 for supporting high-density CHO cell cultures for the fed-batch process intensification.

Toward Best Practices for Controlling Mammalian Cell Culture Environments

The characterization, control, and reporting of environmental conditions in mammalian cell cultures is fundamental to ensure physiological relevance and reproducibility in basic and preclinical biomedical research. The potential issue of environment instability in routine cell cultures in affecting biomedical experiments was identified many decades ago. Despite existing evidence showing variable environmental conditions can affect a suite of cellular responses and key experimental readouts, the underreporting of critical parameters affecting cell culture environments in published experiments remains a serious problem. Here, we outline the main sources of potential problems, improved guidelines for reporting, and deliver recommendations to facilitate improved culture-system based research. Addressing the lack of attention paid to culture environments is critical to improve the reproducibility and translation of preclinical research, but constitutes only an initial step towards enhancing the relevance of in vitro cell cultures towards in vivo physiology.

Bioengineering Outlook on Cultivated Meat Production

Cultured meat (also referred to as cultivated meat or cell-based meat)-CM-is fabricated through the process of cellular agriculture (CA), which entails application of bioengineering, i.e., tissue engineering (TE) principles to the production of food. The main TE principles include usage of cells, grown in a controlled environment provided by bioreactors and cultivation media supplemented with growth factors and other needed nutrients and signaling molecules, and seeded onto the immobilization elements-microcarriers and scaffolds that provide the adhesion surfaces necessary for anchor-dependent cells and offer 3D organization for multiple cell types. Theoretically, many solutions from regenerative medicine and biomedical engineering can be applied in CM-TE, i.e., CA. However, in practice, there are a number of specificities regarding fabrication of a CM product that needs to fulfill not only the majority of functional criteria of muscle and fat TE, but also has to possess the sensory and nutritional qualities of a traditional food component, i.e., the meat it aims to replace. This is the reason that bioengineering aimed at CM production needs to be regarded as a specific scientific discipline of a multidisciplinary nature, integrating principles from biomedical engineering as well as from food manufacturing, design and development, i.e., food engineering. An important requirement is also the need to use as little as possible of animal-derived components in the whole CM bioprocess. In this review, we aim to present the current knowledge on different bioengineering aspects, pertinent to different current scientific disciplines but all relevant for CM engineering, relevant for muscle TE, including different cell sources, bioreactor types, media requirements, bioprocess monitoring and kinetics and their modifications for use in CA, all in view of their potential for efficient CM bioprocess scale-up. We believe such a review will offer a good overview of different bioengineering strategies for CM production and will be useful to a range of interested stakeholders, from students just entering the CA field to experienced researchers looking for the latest innovations in the field.

Strategies for Efficient and Sustainable Protein Extraction and Purification from Plant Tissues

Recombinant proteins produced in whole plants are usually extracted and purified from leaf or seed tissues. Here we describe a workflow that is suitable for most soluble pharmaceutical proteins produced in leafy biomass. We highlight options to streamline the process, reducing the total process time and costs, and eliminating certain unit operations if the product allows. The overall process is a combination of batch-wise or continuous extraction followed by a series of solid-liquid separation steps, which can be supported by chemically defined additives, and concludes with a sequence of optional membrane-based and regular chromatographic purification operations.

Engineering death resistance in CHO cells for improved perfusion culture

The reliable and cost-efficient manufacturing of monoclonal antibodies (mAbs) is essential to fulfil their ever-growing demand. Cell death in bioreactors reduces productivity and product quality, and is largely attributed to apoptosis. In perfusion bioreactors, this leads to the necessity of a bleed stream, which negatively affects the overall process economy. To combat this limitation, death-resistant Chinese hamster ovary cell lines were developed by simultaneously knocking out the apoptosis effector proteins Bak1, Bax, and Bok with CRISPR technology. These cell lines were cultured in fed-batch and perfusion bioreactors and compared to an unmodified control cell line. In fed-batch, the death-resistant cell lines showed higher cell densities and longer culture durations, lasting nearly a month under standard culture conditions. In perfusion, the death-resistant cell lines showed slower drops in viability and displayed an arrest in cell division after which cell size increased instead. Pertinently, the death-resistant cell lines demonstrated the ability to be cultured for several weeks without bleed, and achieved similar volumetric productivities at lower cell densities than that of the control cell line. Perfusion culture reduced fragmentation of the mAb produced, and the death-resistant cell lines showed increased glycosylation in the light chain in both bioreactor modes. These data demonstrate that rationally engineered death-resistant cell lines are ideal for mAb production in perfusion culture, negating the need to bleed the bioreactor whilst maintaining product quantity and quality.

Bax and Bak knockout apoptosis-resistant CHO cell lines significantly improve culture viability and titer in intensified fed-batch culture process

In the field of therapeutic protein production, process intensification strategies entailing higher starting cell seeding densities, can potentially increase culture productivity, lower cost of goods and improve facility utilization. However, increased cell densities often trigger apoptotic cell death at the end of the cell culture process and thus reduce total viable cell count. Apoptosis-resistant Chinese hamster ovary (CHO) cell lines may offer the possibility to diminish this undesired outcome of the intensified production process. In this study, we have generated and tested Bax/Bak double-knock-out (DKO) apoptosis resistant hosts to produce standard and bispecific antibodies, as well as complex molecules in intensified production processes both as pools and single cell clones, and at different scales. In all cases, therapeutic proteins expressed from clones or pools generated from the Bax/Bak DKO hosts showed not only better viability but also enabled extended productivity in the later stages of the 14-day intensified production process. The product qualities of the produced molecules were comparable between Bax/Bak DKO and wild type (WT) cells. Overall, we showed that Bax/Bak DKO apoptosis-resistant host cell lines significantly improve viability and volumetric productivity of the intensified production cultures without altering product qualities. This article is protected by copyright. All rights reserved.

Cell line development for continuous high cell density biomanufacturing: Exploiting hypoxia for improved productivity

Oxygen deficiency (hypoxia) induces adverse effects during biotherapeutic protein production leading to reduced productivity and cell growth. Hypoxic conditions occur during classical batch fermentations using high cell densities or perfusion processes. Here we present an effort to create novel engineered Chinese hamster ovary (CHO) cell lines by exploiting encountered hypoxic bioprocess conditions to reinforce cellular production capacities. After verifying the conservation of the hypoxia-responsive pathway in CHO cell lines by analyzing oxygen sensing proteins HIF1a, HIF1β and VDL, hypoxia-response-elements (HREs) were functionally analyzed and used to create hypoxia-responsive expression vectors. Subsequently engineered hypoxia sensitive CHO cell lines significantly induced protein expression (SEAP) during adverse oxygen limitation encountered during batch fermentations as well as high cell density perfusion processes (2.7 fold). We also exploited this novel cell system to establish a highly effective oxygen shift as innovative bioprocessing strategy using hypoxia induction to improve production titers. Thus, substantial improvements can be made to optimize CHO cell productivity for novel bioprocessing challenges as oxygen limitation, providing an avenue to establish better cell systems by exploiting adverse process conditions for optimized biotherapeutic production.

Perfusion culture of Chinese Hamster Ovary cells for bioprocessing applications

Much of the biopharmaceutical industry's success over the past 30 years has relied on products derived from Chinese Hamster Ovary (CHO) cell lines. During this time, improvements in mammalian cell cultures have come from cell line development and process optimization suited for large-scale fed-batch processes. Originally developed for high cell densities and sensitive products, perfusion processes have a long history. Driven by high volumetric titers and a small footprint, perfusion-based bioprocess research has regained an interest from academia and industry. The recent pandemic has further highlighted the need for such intensified biomanufacturing options. In this review, we outline the technical history of research in this field as it applies to biologics production in CHO cells. We demonstrate a number of emerging trends in the literature and corroborate these with underlying drivers in the commercial space. From these trends, we speculate that the future of perfusion bioprocesses is bright and that the fields of media optimization, continuous processing, and cell line engineering hold the greatest potential. Aligning in its continuous setup with the demands for Industry 4.0, perfusion biomanufacturing is likely to be a hot topic in the years to come.

Benchtop Bioreactors in Mammalian Cell Culture: Overview and Guidelines

Bioreactors are manufactured apparatuses that allow the generation of a specific environment for the highly controlled cultivation of living cells. Originally used for microbial production systems, they have found widespread applications in fields as diverse as vaccine production, plant cell cultivation, and the growth of human brain organoids and exist in equally diverse designs (Chu and Robinson, Curr Opin Biotechnol 12(2):180-187, 2001; Qian et al., Nat Protoc 13:565-580, 2018). Manufacturing of biologics is currently mostly performed using a stirred tank bioreactor and CHO host cells and represents the most "classical" bioreactor production process. In this chapter, we will therefore use the cultivation of suspension Chinese hamster ovary (CHO) cells for recombinant protein production in a stirred tank bioreactor as an example. However, general guidelines provided in this chapter are transferable to different bioreactor types and host cells (Li et al., MAbs 2(5):466-479, 2010).The preparation and operation of a bioreactor (also referred to as upstream process in a biotechnological/industrial setting) is comprised of three main steps: expansion (generation of biomass), production (batch, fed-batch, or continuous process), and harvest. The expansion of cells can last from few days to weeks depending on the number of cells at the start, the cellular doubling time, and the required biomass to inoculate the production bioreactor. The production phase lasts a few weeks and is a highly sensitive phase as the concentration of different chemicals and physical parameters need to be tightly controlled. Finally, the harvest will allow the separation of the product of interest from large particles and then the desired material (cell culture supernatant or cells) is transferred to the downstream process.The raw materials used during the upstream phase (all three steps) need to be aligned with the final purpose of the manufactured product, as the presence of residual impurities may have an impact on suitability of the final product for a desired purpose.

Transient protein expression systems in plants and their applications

The production of recombinant proteins is important in academic research to identify protein functions. Moreover, recombinant enzymes are used in the food and chemical industries, and high-quality proteins are required for diagnostic, therapeutic, and pharmaceutical applications. Though many recombinant proteins are produced by microbial or mammalian cell-based expression systems, plants have been promoted as alternative, cost-effective, scalable, safe, and sustainable expression systems. The development and improvement of transient expression systems have significantly reduced the period of protein production and increased the yield of recombinant proteins in plants. In this review, we consider the importance of plant-based expression systems for recombinant protein production and as genetic engineering tools.

Investigating trace metal precipitation in highly concentrated cell culture media with Pourbaix diagrams

Commercial production of therapeutic proteins using mammalian cells requires complex process solutions, and consistency of these process solutions is critical to maintaining product titer and quality between batches. Inconsistencies between process solutions prepared at bench and commercial scale may be due to differences in mixing time, temperature, and pH which can lead to precipitation and subsequent removal via filtration of critical solution components such as trace metals. Pourbaix diagrams provide a useful tool to model the solubility of trace metals and were applied to troubleshoot the scale-up of nutrient feed preparation after inconsistencies in product titer were observed between bench- and manufacturing-scale batches. Pourbaix diagrams modeled the solubility of key metals in solution at various stages of the nutrient feed preparation and identified copper precipitation as the likely root cause of inconsistent medium stability at commercial scale. Copper precipitation increased proportionally with temperature in bench-scale preparations of nutrient feed and temperature was identified as the root cause of copper precipitation at the commercial scale. Additionally, cell culture copper titration studies performed in bench-scale bioreactors linked copper-deficient mammalian cell culture to inconsistent titers at the commercial scale. Pourbaix diagrams can predict when trace metals are at risk of precipitating and can be used to mitigate risk during the scale-up of complex medium preparations.

Transient ammonia stress on Chinese hamster ovary (CHO) cells yield alterations to alanine metabolism and IgG glycosylation profiles

BACKGROUND

Ammonia concentrations typically increase during mammalian cell cultures, mainly due to glutamine and other amino acid consumption. An early ammonia stress indicator is a metabolic shift with respect to alanine. To determine the underlying mechanisms of this metabolic shift, a Chinese hamster ovary (CHO) cell line with two distinct ages (standard and young) was cultured in parallel fed-batch bioreactors with 0 mM or 10 mM ammonia added at 12 h. Reduced viable cell densities were observed for the stressed cells, while viability was not significantly affected. The stressed cultures had higher alanine, lactate, and glutamate accumulation. Interestingly, the ammonia concentrations were similar by Day 8.5 for all cultures. We hypothesized the ammonia was converted to alanine as a coping mechanism. Interestingly, no significant differences were observed for metabolite profiles due to cell age. Glycosylation analysis showed the ammonia stress reduced galactosylation, sialylation, and fucosylation. Transcriptome analysis of the standard-aged cultures indicated the ammonia stress had a limited impact on the transcriptome, where few of the significant changes were directly related metabolite or glycosylation reactions. These results indicate that mechanisms used to alleviate ammonia stress are most likely controlled post-transcriptionally, and this is where future research should focus.

Study of tissue engineered vascularised oral mucosa-like structures based on ACVM-0.25% HLC-I scaffold in vitro and in vivo

PURPOSE

To explore the feasibility of constructing tissue-engineered vascularised oral mucosa-like structures with rabbit ACVM-0.25% HLC-I scaffold and human gingival fibroblasts (HGFs), human gingival epithelial cells (HGECs) and vascular endothelial-like cells (VEC-like cells).

METHOD

Haematoxylin and Eosin (H&E) staining, immunohistochemical, immunofluorescence, 5-ethynyl-2'-deoxyuridine (EdU) staining and scanning electron microscope (SEM) were performed to detect the growth status of cells on the scaffold complex. After the scaffold complex implanted into nude mice for 28 days, tissues were harvested to observe the cell viability and morphology by the same method as above. Additionally, biomechanical experiments were used to assess the stability of composite scaffold.

RESULTS

Immunofluorescence and Immunohistochemistry showed positive expression of Vimentin, S100A₄ and CK, and the induced VEC-like cells had the ability to form tubule-like structures. In vitro observation results showed that HGFs, HGECs and VEC-like had good compatibility with ACVM-0.25% HLC-I and could be layered and grow in the scaffold. After implanted, the mice had no immune rejection and no obvious scar repair on the body surface. The biomfechanical test results showed that the composite scaffold has strong stability.

CONCLUSION

The tissue-engineered vascularised complexes constructed by HGFs, HGECs, VEC-like cells and ACVM-0.25% HLC-I has good biocompatibility and considerable strength.

Automation of high CHO cell density seed intensification via online control of the cell specific perfusion rate and its impact on the N-stage inoculum quality

Current CHO cell production processes require an optimized space-time-yield. Process intensification can support achieving this by enhancing the productivity and improving facility utilization. The use of perfusion at the last stage of the seed train (N-1) for high cell density inoculation of the fed-batch N-stage production culture is a relatively new approach with few industry applicable examples. Within this work, the impact of the cell-specific perfusion rate (CSPR) of the N-1 perfusion and the relevance of its control for the quality of generated inoculation cells was evaluated using an automated perfusion rate (PR) control based on online biomass measurements. Precise correlations (R² = 0.99) between permittivity and viable cell counts were found up to the high densities of 100⋅10⁶ c·mL^-1. Cells from N-1 perfusion were cultivated at a high and low CSPR with 50 and 20 pL·(c·d)^-1, respectively. Lowered cell growth and an increased apoptotic reaction was found as a consequence of the latter due to nutrient limitations and reduced uptake rates. Subsequently, batch cultivations (N-stage) from the different N-1 sources were inoculated to evaluate the physiological state of the inoculum. Successive responses resulting from the respective N-1 condition were uncovered. While cell growth and productivity of approaches inoculated from high CSPR and a conventional seed were comparable, low CSPR inoculation suffered significantly in terms of reduced initial cell growth and impaired viability. This study underlines the importance to determine the CSPR for the design and implementation of an N-1 perfusion process in order to achieve the desired performance at the crucial production stage.

Process intensification to produce a difficult-to-express therapeutic enzyme by high cell density perfusion or enhanced fed-batch

Intensified bioprocesses have caught industrial interest in the field of biomanufacturing in recent years. Thanks to new technology, intensified processes can support high cell densities, higher productivities and longer process times, which together can offer lower cost of goods. In this study two different intensified process modes, high cell density perfusion and enhanced fed-batch, were evaluated and compared with a conventional fed-batch process for a difficult-to-express therapeutic enzyme. The intensified process modes were cultivated with a target cell density of 100 × 10⁶  cells/ml and with alternating tangential flow filtration, ATF, as cell retention device. The processes were designed to resemble an established optimized fed-batch process using the knowledge of this process without new dedicated optimization for the intensified modes. The design strategy included decision of the ratio of feed concentrate to base medium and glucose supplementation, which were based on target cell-specific consumption rates of key amino acids and glucose, using a targeted feeding approach (TAFE). A difficult-to-express therapeutic enzyme with multiple glycosylation sites was expressed and analyzed in the different production processes. The two new intensified processes both achieved 10 times higher volumetric productivity (mg/L/day) with retained protein quality and minor changes to the glycan profile compared to the fed-batch process. The study demonstrates the potential of using intensified processes for sensitive complex enzymes. It is shown here that it is possible to transfer a developed fed-batch process into high cell density processes either in intensified fed-batch or steady-state perfusion without new dedicated optimization. The results demonstrated as well that these intensified modes significantly increase the productivity while maintaining the desired product quality, for instance the same amount of product was obtained in 1 day during the perfusion process than in a whole fed-batch run. Without any prior optimization of the perfusion rate, the high cell density perfusion process resulted in only 1.2 times higher medium cost per gram produced protein.

A novel approach to residence time distribution characterization in a mAb continuous process

Residence time distribution modeling of integrated perfusion to capture process can elucidate the impact of product quality excursions and filter fouling on monoclonal antibody production. In this case study, a glycosylation inhibitor and fluorescently labeled antibody are applied to the continuous process to study protein quality modulation, perfusion filter fouling, and unit operation hold times. The unit operations were modeled as continuous-stirred tank reactors and the residence time distribution of a small molecule glycan inhibitor and impact on glycosylation were characterized. A fluorescently labeled antibody was applied as a tracer molecule and confirmed the impact of packed cell volume and filter fouling. This study demonstrates how a biologics continuous process can be modeled and characterized through residence time distribution to ensure a robust, well-understood process.

End-to-end continuous bioprocessing: Impact on facility design, cost of goods, and cost of development for monoclonal antibodies

This article presents a systematic approach to evaluate the business case for continuous processing that captures trade-offs between manufacturing and development costs for monoclonal antibodies (mAbs). A decisional tool was built that integrated cost of goods (COG) with the cost of development models and new equipment sizing equations tailored to batch, hybrid, and end-to-end continuous processes. The COG analysis predicted that single-use continuous facilities (sized using a dedicated downstream processing train per bioreactor) offer more significant commercial COG savings over stainless steel batch facilities at annual demands of 100-500 kg (~35%), compared to tonnage demands of 1-3 tons (~±10%) that required multiple parallel continuous trains. Single-use batch facilities were found to compete with continuous options on COG only at 100 kg/year. For the scenarios where batch and continuous facilities offered similar COG, the analysis identified the windows of operation required to reach different COG savings with thresholds for the perfusion rate, volumetric productivity, and media cost. When considering the project lifecycle cost, the analysis indicated that while end-to-end continuous facilities may struggle to compete on development costs, they become more cost-effective than stainless steel batch facilities when considering the total out-of-pocket cost across both drug development and commercial activities.

Antibody capture process based on magnetic beads from very high cell density suspension

Cell clarification represents a major challenge for the intensification through very high cell density in the production of biopharmaceuticals such as monoclonal antibodies (mAbs). The present report proposes a solution to this challenge in a streamlined process where cell clarification and mAb capture are performed in a single step using magnetic beads coupled with protein A. Capture of mAb from non-clarified CHO cell suspension showed promising results; however, it has not been demonstrated that it can handle the challenge of very high cell density as observed in intensified fed-batch cultures. The performances of magnetic bead-based mAb capture on non-clarified cell suspension from intensified fed-batch culture were studied. Capture from a culture at density larger than 100 × 10⁶ cells/ml provided an adsorption efficiency of 99% and an overall yield of 93% with a logarithmic host cell protein (HCP) clearance of ≈2-3 and a resulting HCP concentration ≤≈5 ppm. These results show that direct capture from very high cell density cell suspension is possible without prior processing. This technology, which brings significant benefits in terms of operational cost reduction and performance improvements such as low HCP, can be a powerful tool alleviating the challenge of process intensification.

Trends in Monoclonal Antibody Production Using Various Bioreactor Syst

Monoclonal antibodies are widely used as diagnostic reagents and for therapeutic purposes, and their demand is increasing extensively. To produce these proteins in sufficient quantities for commercial use, it is necessary to raise the output by scaling up the production processes. This review describes recent trends in high-density cell culture systems established for monoclonal antibody production that are excellent methods to scale up from the lab-scale cell culture. Among the reactors, hollow fiber bioreactors contribute to a major part of high-density cell culture as they can provide a tremendous amount of surface area in a small volume for cell growth. As an alternative to hollow fiber reactors, a novel disposable bioreactor has been developed, which consists of a polymer-based supermacroporous material, cryogel, as a matrix for cell growth. Packed bed systems and disposable wave bioreactors have also been introduced for high cell density culture. These developments in high-density cell culture systems have led to the monoclonal antibody production in an economically favourable manner and made monoclonal antibodies one of the dominant therapeutic and diagnostic proteins in biopharmaceutical industry.

Process and operations strategies to enable global access to antibody therapies

Few monoclonal antibodies are currently approved for treating infectious diseases, but multiple products are in development against a broad range of infectious diseases, including Ebola, influenza, hepatitis B, HIV, dengue, and COVID-19. The maturity of mAb technologies now allow us to identify and advance neutralizing mAb products to the clinic at "pandemic pace", as the pipeline of mAbs targeting SARS-CoV-2 has demonstrated. Ensuring global access to these products for passive immunization, however, will require both low manufacturing cost and multi-ton production capacity-particularly for those infectious diseases where the geographic burden falls mostly in low- and middle-income countries or those with pandemic potential. Analysis of process economics and manufacturing technologies for antibody and other parenteral protein therapeutics demonstrates the importance of economies of scale to reducing the cost of goods for drug substance manufacturing. There are major benefits to convergence on a standardized platform process for antibody production that is portable to most existing very large-scale facilities, carries low risk for complications during process transfer and scale-up, and has a predictable timeline and probability of technical and regulatory success. In the case of an infectious disease with pandemic potential which could be treated with an antibody, such as COVID-19 or influenza, these advantages are paramount.

High density bioprocessing of human pluripotent stem cells by metabolic control and in silico modeling

To harness the full potential of human pluripotent stem cells (hPSCs) we combined instrumented stirred tank bioreactor (STBR) technology with the power of in silico process modeling to overcome substantial, hPSC‐specific hurdles toward their mass production. Perfused suspension culture (3D) of matrix‐free hPSC aggregates in STBRs was applied to identify and control process‐limiting parameters including pH, dissolved oxygen, glucose and lactate levels, and the obviation of osmolality peaks provoked by high density culture. Media supplements promoted single cell‐based process inoculation and hydrodynamic aggregate size control. Wet lab‐derived process characteristics enabled predictive in silico modeling as a new rational for hPSC cultivation. Consequently, hPSC line‐independent maintenance of exponential cell proliferation was achieved. The strategy yielded 70‐fold cell expansion in 7 days achieving an unmatched density of 35 × 10⁶ cells/mL equivalent to 5.25 billion hPSC in 150 mL scale while pluripotency, differentiation potential, and karyotype stability was maintained. In parallel, media requirements were reduced by 75% demonstrating the outstanding increase in efficiency. Minimal input to our in silico model accurately predicts all main process parameters; combined with calculation‐controlled hPSC aggregation kinetics, linear process upscaling is also enabled and demonstrated for up to 500 mL scale in an independent bioreactor system. Thus, by merging applied stem cell research with recent knowhow from industrial cell fermentation, a new level of hPSC bioprocessing is revealed fueling their automated production for industrial and therapeutic applications.

A common framework for integrated and continuous biomanufacturing

There is a growing application of integrated and continuous bioprocessing (ICB) for manufacturing recombinant protein therapeutics produced from mammalian cells. At first glance, the newly evolved ICB has created a vast diversity of platforms. A closer inspection reveals convergent evolution: nearly all of the major ICB methods have a common framework that could allow manufacturing across a global ecosystem of manufacturers using simple, yet effective, equipment designs. The framework is capable of supporting the manufacturing of most major biopharmaceutical ICB and legacy processes without major changes in the regulatory license. This article reviews the ICB that are being used, or are soon to be used, in a GMP manufacturing setting for recombinant protein production from mammalian cells. The adaptation of the various ICB modes to the common ICB framework will be discussed, along with the pros and cons of such adaptation. The equipment used in the common framework is generally described. This review is presented in sufficient detail to enable discussions of IBC implementation strategy in biopharmaceutical companies and contract manufacturers, and to provide a road map for vendors equipment design. An example plant built on the common framework will be discussed. The flexibility of the plant is demonstrated with batches as small as 0.5 kg or as large as 500 kg. The yearly output of the plant is as much as 8 tons.