Recombinant antibodies can be defined by comparison with conventional monoclonal antibodies. In this article, we cover the essential definition of recombinant antibodies and explain why these reagents are quickly replacing conventional monoclonal antibodies from hybridomas in many applications. Check out other frequently asked questions (FAQs) about recombinant antibodies on our dedicated page.

Monoclonal versus Recombinant antibodies

In a nutshell, recombinant antibodies are monoclonal antibodies produced in highly productive recombinant expression systems. These molecules are manufactured by cloning antibody-encoding genes into expression vectors, transfecting or transforming expression systems (bacterial, yeast, insect, plant, or mammalian) with these vectors, selecting positive clones (mostly in stable systems or recombinant non-mammalian systems), and scaling up production.

Although the two terms are often used interchangeably, some experts still use them to differentiate between monoclonal antibodies natively produced in hybridomas (i.e. cell culture supernatant or through the ascites method) and recombinant antibodies produced in high-yield expression systems.

In this sense, monoclonal antibodies are rarely used for therapeutic applications due to the instability of hybridoma cell lines (prone to losing antibody-encoding genes) and difficulties in scaling-up production. For the past decades, large-scale production of antibodies for therapeutic applications has relied on recombinant technology. And as the demand for these molecules continues to grow, the production costs continue to decline.

In contrast, native monoclonal antibodies from hybridomas are still recurrently used for small-scale applications like research and diagnostics. In these cases, the ease of transfer of hybridoma cell lines between labs (at times mediated by hybridoma cell banks) is often considered as an advantage by researchers.

Another important difference between monoclonal and recombinant antibodies is that the former relies on animal-dependent methods and the latter uses only animal-free technologies. Recombinant antibodies only require a sequence to be produced in vitro. These sequences can be obtained from different sources including hybridomas, antibody libraries, or single-cell sequencing. With the exception of hybridomas, most other sources of antibody sequences do not require the extensive use of animals.

Why there is a growing demand for recombinant antibodies?

Despite monoclonal antibodies being the norm for many diagnostic and research applications, recombinant antibodies are quickly replacing them. Unlike hybridomas, the recombinant technology allows researchers to manipulate the structure of antibodies and obtain more consistent and higher production yields in comparison to conventional production processes.

Also, the growing demand for antibody reagents is also pushing the field towards standardization. This requires a greater level of purity (not easily obtained when antibodies are produced by hybridomas) and more thorough characterization of these molecules in regards to affinity, potential cross-reactivity, performance in specific applications, epitope-specificity, among others.

Conventional monoclonal antibodies produced in hybridomas cannot achieve the same quality standards reached by recombinant antibodies. For this reason, many laboratories around the world are changing towards recombinant production processes to increase the accuracy of their antibody-based tools.

Nevertheless, this shift in the field is still lagging for some applications.

This is tied to the difficulties in changing established protocols in companies and institutions. In this case, the development of specific kits for recombinant antibody production may propel the faster integration of this process into existing platforms.

Concluding remarks

Recombinant antibodies are invaluable tools for many applications. They differ from monoclonal antibodies in the way they are produced. These molecules are typically produced in high-yield mammalian expression systems like Chinese hamster ovary (CHO) and Human embryonic kidney (HEK) cells.

As production costs continue decreasing and recombinant production becomes more accessible and easier to adopt, recombinant antibodies are expected to replace monoclonal antibodies produced in hybridomas (cell culture supernatant and ascites) for many applications.