cGMP Cell Line Development and Commercial Manufacture
MedScope has substantial experience contracting with the regulatory and manufacturing aspects of development of stable cell lines, including 1) transfection of selected host cells (eg. typically CHO or HEK 293 cells) with desired plasmids, 2) screening and quantification of high-expressing clones, 3) verification of clone cells identified as stable high producers, and 4) validation of those selected cell lines and/or the expression proteins produced by the cell line of interest (particularly in terms of cell and/or protein yield). MedScope is a rapid development organization, and in most instances can initiate value-based discussions within 24 hours. Please contact us at 802-236-8650 or info@medscope.com.
Key Cell Line Regulatory/Development/Optimization Issues In cGMP Cell Line Development and Manufacture
- Optimizing current CHO cell-based expression platforms (DG44 and GS systems) to achieve high productivity eg. express at minimum monoclonal therapeutic antibodies with titers of more than 5 g/L
- Creating cell lines having the appropriate quality eg. structure of the molecule needs to be ‘as expected’, cannot have molecules with unintended clippings (eg. due to the presence of certain proteolytic enzymes, etc.) or unintended modifications of amino acids which can be detrimental for the efficacy/safety of the product
- Creating cell lines with a suitable glycan pattern (for lines expressing human antibodies)
- Cell lines need to be robust enough to grow to high density in large bioreactors
- Developing strategies for choosing the expression vector.
- Monitoring CHO cell based genetics and physiology to maximize protein production
- Identification of mammalian cells transfection methods
- Selection of recombinant clones
- Manual and automatic methods for screening the best producers
- Gene editing tools (CRISPR, TALEN, ZNF...) for Metabolic engineering
- Creating best nutritional and environmental conditions for maximum recombinant protein production
- Detection and analysis of the protein of interest (SDS-PAGE, Western blot, ELISA, Blitz...)
- Cell banking (cryopreservation) and quality control (mycoplasma detection...)
- Host Cell cGMP Cell Line Testing:
- test of cell´s identity (e.g. short tandem repeat analysis),
- test of purity (absence of adventitious cellular/icrobial contaminants/cross-contaminations with other cell lines)
- in vitro, in vivo, and polymerase chain reaction (PCR)-based assays for adventitious agents.
- tests for tumorigenicity of the cells and oncogenicity of the cell´s genomic DNA as needed
- quality checks with respect to virus contamination
Cell Line Production Yield - mAb
Cell line development workflow In order to generate high yields of recombinant protein products, stable cell lines such as hybridoma, CHO, or HEK 293 are typical vehicles of choice. The process of developing stable cell lines starts with transfecting host cells with recombinant plasmids. In the case of mAb production, the traditional approach is to generate mAb-producing cells (i.e. hybridomas) by fusing myeloma cells with desired antibody-producing splenocytes (e.g. B cells). These B cells are typically sourced from animals, usually mice. After transfection or cell fusion, large numbers of clones are screened and selected on the basis of expression (e.g. CHO cell lines) or antigen specificity and immunoglobulin class (e.g. hybridoma cell lines). Once candidate cell line clones are identified, each “hit” is confirmed, validated, and characterized using a variety of downstream functional assays. Upon completion, the clones are expanded or scaled up where additional downstream bioprocesses occur.
Development Bottlenecks in Cell Line Development
One of many bottlenecks in this form of cell line development is the time-consuming and labor-intensive process of manual cell screening. Cell line development requires the discovery of single cell-derived clones that produce high and consistent levels of the target therapeutic protein. The first step in the process is the isolation of single, viable cells. Limiting dilution is a technique that relies on statistical probability but is time consuming.
High Throughput, Automated Solutions To Cell Screening
The ability to select cells based on surface protein expression is of great use in establishing cell lines expressing the receptor(s) of interest for downstream phenotyping/genotyping, basic discovery research, or as a cell line for cell based assays and screening. Historically, such separation of cells has been achieved using automated Fluorescence Activated Flow Cytometry (FACS) to sort cell-based protein expression.
Higher Throughput, Automated Solutions To Cell Screening
ClonePix 2 System: technology utilizes ability to grow and isolate mammalian cells into clonal colonies suspended in semisolid media AND image these colonies using fluorescent assays and markers. Example use of this technology is to sort cells using high-res imaging in either brightfield or optional fluorescence and capture 5 images per each single cell deposit. This technique can be used to prove monoclonality, improve efficiency, maintain and enrich cell viability, and prevent cross- contamination using the CloneSelect™ Single-Cell Printer™ Series which can deposit single cells gently and with high efficiency using a patented, inkjet-like disposable, oneway dispensing cartridge.Using ClonePix 2 fluorescence imaging technology, this high-powered alternative to flow cytometry enables users to select the highest expressers for a particular receptor or combination of receptors/cell surface proteins, which results in monoclonal populations of cells as opposed to the enriched top 5% that FACS produces that are not clonal and require further serial dilution to establish monoclonality.
How To Reach Us
MedScope is a rapid development organization, and in most instances can initiate and address a wide range of value-based discussions within 24 hours. Our teams and wide technological network in the biopharmaceutical industry enables us to quickly bring substantial knowledge and problem solving skills to help you quickly solve problems. For rapid response, please contact us at 802-236-8650 or info@medscope.com.
