Stable cell line generation for monoclonal antibody production is one of the most crucial steps to ensure the commercial viability of new biotherapeutics and diagnostic tools. Despite being an expensive, time and labor-intensive process, stable expression is currently the only suitable method for the production of large quantities of monoclonal antibodies. In this article, we explain the benefits of using stable cells for monoclonal antibody production and how to maximize the success of this approach and ensure commercial viability. Check out other frequently asked questions (FAQs) about stable cell lines for monoclonal antibody production on our dedicated page.

Advantages of the stable cell lines for antibody production

Stable cell line generation is an expensive, labor and time-intensive process used in the production of recombinant monoclonal antibodies. For this reason, it is reserved for the large-scale production of antibodies with a commercial value like the ones used for therapeutic and diagnostic applications (i.e. in vitro and medical devices).

The stable integration of antibody-encoding genes in the genome of an expression host has several advantages in comparison to transient and native expression processes including:

  • Optimal productivity
  • Superior batch-to-batch consistency
  • Reproducible production process
  • Amenable to scaling up
  • Ease of cell and protocol transference
  • Ease of protocol standardization
  • Fast generation of large amounts of monoclonal antibodies once stable cells are fully developed

Alternative methods to stable antibody production and their limitations

The two most commonly used alternative processes of monoclonal antibody production consist of transient production in recombinant mammalian systems and native production in hybridoma cell lines. Both these systems have considerable bottlenecks, the most important of which is their incompatibility with large-scale production processes.

Hybridomas suffer from many well-known production issues including the proclivity antibody genes due to genetic drift, difficulties in growing in serum-free media (free of contaminants), and high batch-to-batch inconsistencies. Recombinant transient expression in highly productive cell lines partially solves these issues. With superior batch-to-batch consistencies and the ability to grow in serum-free medium, transient expression systems are now one of the most important methods for fast monoclonal antibody production.

However, as the name indicates, transient systems are only a temporary solution. Since mammalian systems are unable to replicate plasmids, transient transfection achieves only the short-term and small-scale production of antibodies.

For this reason, stable cell line generation continues to be one of the most crucial steps to secure the commercial viability of monoclonal antibodies. Thus, to ensure the process generates highly productive cell lines, several factors should be considered before initiating this procedure.

Increasing the success rates of the stable cell line generation process

One of the most important aspects antibody developers can examine before committing to stable cell line development is their antibody’s developability.

Developability can be defined as the feasibility or probability of the successful development of a lead candidate from the discovery to the large-scale manufacturing stage. In recent years, researchers became aware that developability can be predicted early in the development process by assessing key antibody physicochemical properties.

The properties with the greatest impact on developability are:

  • Antibody stability in storage conditions, specifically the degradation profile at different temperatures
  • Antigen specificity that can be defined by the epitope bound by the antibody and selectivity defined by the uniqueness of the epitope – is it a conserved epitope shared by different proteins or an epitope found in variable regions?
  • Affinity and avidity – the first can be defined by how strongly an antibody binds to an antigen and the second, also known as functional affinity, as the overall strength of the antibody-antigen complex
  • Antibody’s proclivity to form aggregates – antibodies that form aggregates have low solubility and limited therapeutic efficiency
  • Immunogenicity is hard to predict during early development, but many in silico models are currently available for predicting immunogenicity

Most of these properties can be determined during lead screening stages using only small quantities of antibodies. The small-scale production of antibodies can be achieved using transient expression in mammalian systems (more similar to the cells used for stable cell line development) and the early testing of these leads significantly increases the manufacturability of biotherapeutics and antibody-based diagnostic tools.

Concluding remarks

Stable cell line generation is currently the only method ensuring the commercial viability of monoclonal antibodies. However, many antibodies fail to reach the market due to production issues. For this reason, early testing of key antibody properties (aggregation, stability, affinity, specificity, etc.) is vital to improve success rates and decrease overall production costs.

Bailly, M. et al. Predicting Antibody Developability Profiles Through Early Stage Discovery Screening. MAbs. 2020; 12(1): 1743053. doi: 10.1080/19420862.2020.1743053