With current advances in technology and biopharmaceutical research, cell line development (CLD) has become a prominent process in many application areas. One of these areas would be the development of biotherapeutics, including a variety of monoclonal antibodies, vaccines, and biologics. The development of such new medical treatments has seen a sharp increase in demand for better quality and safety standards. To meet the increasing demand for these types of products, researchers rely on different mammalian expression-based systems, with CHO cells being the most popular system for large-scale industrial culturing.
Types of Cell Line Development
CHO cell development
Chinese hamster ovary (CHO) cells are commonly used in industry for the production of monoclonal antibodies and recombinant proteins. They comprise a variety of lineages including CHO-DXB11, CHO-K1, CHO-DG44, and CHO-S. Despite all CHO cell lines sharing a common ancestor, extensive mutagenesis, and clonal selection have resulted in substantial genetic heterogeneity among them.
Hybridoma cell development
Hybridomas are generated by fusing spleen cells (plasma cells) from immunized hosts with a compatible myeloma cell line (malignant and immortal plasma cell line). Cell fusion between myelomas and plasma cells is recurrently induced by electric pulses (electrofusion) or polyethylene glycol (PEG).
This is the process of introducing foreign DNA (encoding the recombinant protein of interest) into a host cell. A small population of cells with foreign DNA integrated into their genome that maintain their ability to express recombinant protein for long periods are referred to as stably transfected cells.
Antibodies screening/titer ranking
Discovery and selection of high-value clones from a transfected pool of cells. Screening large populations by quantifying cell surface expression of protein-of-interest or secreting antibodies (titer ranking) will increase the probability of finding rare high-affinity binders or high producers.
Single-cell isolation and cell viability
Single, viable cells must be isolated and cloned to ensure that the cell population is genetically identical, significantly reducing the heterogeneity of expression.
When developing cell lines for biotherapeutics, it is crucial from a quality and regulatory perspective to ensure that the cell line originates from a single progenitor and is therefore monoclonal. Documentation of monoclonality (a regulatory metric for therapeutic cell lines) is typically image-based, whereby an image of a single cell is recorded and included in regulatory filings.
Clone productivity screening and titer
This is a test that detects the amount of recombinant protein or antibodies produced from the clonally-derived cell line.
Methods for the Development of Cell Lines
- Cell surface expression screening
Cell surface proteins have a wide range of biological functions, which are often used as lineage-specific markers. Rapid characterization of the cell surface markers could not only lead to the identification and development of new diagnostic markers and therapeutic targets but also provide insight into the basic biology of diseases.
Cell line development requires the discovery of single cell-derived clones that produce high and consistent levels of the target therapeutic protein. A critical first step in the process is the isolation of single, viable cells. Single cells proliferate to form colonies that can then be assessed for the productivity of the target therapeutic protein.
Clone productivity screening and titer
An important component in identifying high-value clones is determining the productivity of single-cell-derived colonies.
Colony picking is an essential step in biological research as scientists often need to isolate high-value clones to mass-produce DNA or proteins to be used in a variety of applications downstream.
Creative Bioarray Relevant Recommendations
Creative Bioarray provides CHO and hybridoma cells, such as CHO-SSR1, CHO-SSR2, CHO-DHFR, animal hybridoma cells, and others. In addition, We provide the full cell surface markers validation services from experimental design to specimen progress, acquisition, and data analysis. We also offer a wide selection of cell viability assays.