Recombinant antibody technology has helped overcome a wide range of common issues linked to hybridoma platforms, enabling the development of a new class of biological drugs. This powerful technology continues to underpin the discovery and development of antibody-based therapeutics, as well as helping improve novel modalities’ performance.
Suranjana Sen, Ph.D., Technical Account Manager, Sino Biological. Image Credit: Sino Biological Inc.
Drivers of the recombinant approach
The development of early monoclonal antibody (mAb) therapies centered around the hybridoma platform requires the production of target antigen or immunogen and animal immunizations.
This means there are ethical issues surrounding hybridoma technology and other challenges, including antibody heterogeneity, batch-to-batch variability, loss of antibody productivity, and limitations in cost and scale.
The process is also time-consuming, often requiring several months from immunization before specific hybridoma clones are established and mAb production begins.1,2
Recombinant DNA technology can generate recombinant antibodies from host cell lines. This approach significantly reduces reliance on animal use and allows for the rapid production of large quantities of products within just a few weeks in most instances.3,4
Recombinant antibodies are based on known DNA sequences, meaning replicating them is straightforward. Their production is also highly controlled, consistent, and reproducible.5
Recombinant antibodies also offer many other advantages, including being amenable to antibody engineering and effectively targeting hybridoma-refractory antigens.
The advantages of engineering
Recombinant antibody engineering has excellent potential, empowering users to create unique molecules with the ideal attributes to treat specific diseases. For example, it is possible to modify the fragment crystallizable (Fc) region to prevent initiation of any undesired responses while designing minute variable regions designed to more effectively bind to the target.6
Humanizing antibodies initially discovered in mice or other animals to reduce their potential immunogenicity is also possible.
The field’s years of experience working with recombinant antibody engineering give researchers and engineers confidence in which changes are necessary to realize specific benefits.
Advances in artificial intelligence (AI) algorithms will see ongoing increases in predictability, with many drug developers already leveraging AI technologies to effectively predict and analyze potential therapeutics from antibody sequences before commencing production.7,8
Discovery and development are further accelerated through high-throughput recombinant antibody production and characterization to validate these predictions in the wet lab. Platform processes are also vital in enabling the rapid scale-up of recombinant antibody production to meet commercial and clinical demand.
Fragment understanding
A notable benefit of recombinant antibody technology is its capacity for exploring and understanding different flavors of mAbs, with its versatility in this regard limited only by the imagination.
The use of engineered antibody fragments as biopharmaceuticals has risen recently, with monovalent formats like Fab, scFv, VHHl, and bispecific constructs such as BiTE and Diabody seeing more widespread use.
Conventional mAbs exhibit some limitations when used in clinical applications. For example, Immunoglobulin G (IgG) molecules are comparatively large (~150 kDa), potentially limiting their ability to effectively penetrate into tissues. The presence of the Fc region in the IgG molecule can also mediate bystander activation of the immune system.
Despite these limitations, antibody fragments retain the targeting specificity of intact mAbs while also boasting beneficial properties that make them highly suited to various diagnostic and therapeutic applications.
Their small size means that antibody fragments offer improved tissue penetration, reduced immunogenicity, and the ability to bind to historically inaccessible epitopes. These fragments also offer structural flexibility and relatively straightforward production and engineering. They can also serve as building blocks for novel constructs.
Producing and purifying antibody fragments requires extensive expertise, particularly given the recent increase in fragment design complexity and diversification.
It is necessary to consider several aspects, including design strategies, the need for upstream production to maintain high productivity while minimizing impurities, and any potential downstream processing requirements required to produce the desired fragment in a highly pure form.9
Modifications for research, diagnostic, and therapeutic applications
Antibodies employed in research, diagnostic, and therapeutic applications must exhibit high binding affinity and specificity, but other aspects must be considered in relation to each application. For example, biomedical researchers require antibodies capable of penetrating different tissues to evaluate a range of molecular and behavioral characteristics.
Antibody fragments offering superior tissue penetration to full-length IgG are best suited to these applications. Engineered multivalent antibodies featuring enhanced antigen-binding avidity represent promising agents in diagnostics.10,11,12
Recombinant antibodies can be modified in endless ways to accommodate various therapeutic applications. These antibodies can be customized to achieve various desired characteristics, including targeting effector cells more strongly, avoiding cross-reactivity, and enabling site-specific conjugation to small molecule payloads.
Unlocked potential
There is a great deal of excitement surrounding the therapeutic possibilities of cell and gene therapies, as well as other novel modalities.
Recombinant antibodies offer significant potential and it is anticipated that they will continue to play a central role in advancing treatments for a range of human diseases, including cancer and metabolic, autoimmune, and infectious diseases. Much of this potential stems from recombinant antibodies’ capacity to enable targeted therapies with minimal side effects.13
In addition to mAbs, antibody fragments, bispecific, antibody-drug conjugates, and other next-generation antibody therapeutics offer a range of novel functionalities, boasting even more improved targeting abilities and, therefore, enhanced efficacy.
From a diagnostic perspective, recombinant antibodies facilitate the highly sensitive and selective detection of specific biomarkers present at various disease stages, enabling the development of tailored treatments that are specifically focused on disease progression.
Innovations in targets and expected modifications
The recombinant antibody sector is expected to see continued growth, expanding to include a wider variety of novel targets and modifications. More in-depth insight into genomic and proteomic changes associated with diseases has led to the emergence of new targets for which no antibody drugs are currently available.
There remains a significant gap between target discovery and the development of corresponding therapeutic antibodies. Recombinant antibodies are increasingly used in medicine, due to their potential to enable precise design, powerful engineering, and efficient production, helping to address the pressing need to develop antibodies for these novel entities.
A number of critical steps are required to provide the optimal affinity, specificity, and other properties required for a given target or application. These include an improved understanding of the design landscape, an investigation into various known and unknown opportunities, and the identification of the ideal engineering steps required.
Further revolutionary advances throughout the recombinant antibody field are expected in the near future, with antibody therapies becoming available for targets that are currently unthinkable.
The role of recombinant antigens and antibodies in the COVID-19 pandemic response
The COVID-19 pandemic involved a tragic global loss of life, though it also highlighted the many positive aspects of the biopharma industry that the general public is not normally aware of.
Sino Biological worked throughout the pandemic to produce vital research reagents and offer contract research services to biopharma and diagnostic labs looking to advance SARS-CoV-2-specific vaccines, therapeutics, and immunodiagnostic assays.
The company offers a diverse and wide-ranging portfolio of recombinant antigens and antibodies for SARS-CoV-2. Sino Biological has supported scientists worldwide in their research, which has already led to more than 2,000 publications.
Sino Biological was able to develop reagents and implement contract research services extremely rapidly during the pandemic. The company produced the key SARS-CoV-2 spike protein reagents in January 2020 within a record 11 days, while in December 2021, it developed the Omicron RBD protein in a new record of just six days.
Each of these proteins was developed and manufactured via the company’s proprietary recombinant platforms. Sino Biological has been actively tracking the emergence of new variants since the COVID-19 outbreak to ensure its products are as up-to-date as possible, and its SARS-CoV-2 reagent portfolio covers all current variants under monitoring (VUMs) and variants of interest (VOIs).
Sino Biological has also developed ProVir® - the world’s most comprehensive viral antigen bank featuring antibodies for almost all of the most notable viral antigens, as well as antibody pairs boasting high specificity and sensitivity.
These antigens significantly impact vaccine, therapeutic, and diagnostic research in many areas of virology and immunology, including COVID-19, influenza, and RSV.
Tailoring supply to meet client needs
Organizations throughout the biopharma industry are increasingly working with contract research organizations (CROs) to develop and produce custom antibodies. This approach allows organizations to leverage CROs’ advanced technologies, specialized expertise, and established platforms to mitigate risks, reduce costs, and save time.
Recombinant technology also affords organizations greater possibility and flexibility, allowing them to tailor production in line with precise application needs. This flexibility, coupled with the ever-increasing diversification and complexity of antibody-based biopharmaceuticals, has continued to drive the trend toward widespread outsourcing.
Discussions about outsourcing tend to start with a discussion of the specific end application, followed by a comprehensive review of the target antigen and any particular requirements regarding the design, engineering, and production of the desired antibody against the target.
It is important to ensure that best-fit strategies are in place to meet the client's needs to generate high-performing antibodies with the appropriate properties for specific applications.
Sino Biological: Building recombinant antibody expertise for over 15 years
Sino Biological has been leveraging recombinant technology from the outset, allowing it to generate its catalog protein and antibody products as well as maintain a robust contract development and manufacturing business.
There is a powerful drive to continually fine-tune and advance the company’s capabilities in both these areas. For example, Sino Biological has worked closely with COVID-19 therapy and vaccine developers, while continuing to deliver custom services for developers of novel therapies and diagnostic products.
A plethora of platforms
Sino Biological boasts a comprehensive array of expression platforms, allowing it to accommodate its customers' diverse needs. These platforms range from fast and efficient cell-free platforms to cell-based production platforms, such as mammalian cell and baculovirus-insect cell expression systems.
Mammalian cell expression
The production of recombinant proteins and antibodies from mammalian cells offers many advantages in human research or clinical studies.
The use of mammalian cells allows the manufacture of proteins or antibodies that mimic nature, with the proper posttranslational modifications executed on the molecule itself.
Sino Biological’s highly optimized mammalian cell expression platforms benefit from the use of a range of proprietary culture media, transfection reagents, expression vectors, supplements, and boosters.
The company’s high-throughput platform is able to accommodate over 1,000 projects at the same time, with products ranging from genes to recombinant antibodies designed for discovery and screening purposes. This robust platform means that a customer can receive over 1,000 different antibodies in only two weeks.
Sino Biological can also provide products on scales ranging from micrograms to kilograms, ensuring that customers worldwide benefit from high-quality, consistent products in whatever quantity they require.
Cell-free synthesis
Cell-free systems facilitate the rapid production of proteins and antibodies in vitro with no need to utilize living cells. Typical protein and antibody synthesis in cell-free systems takes a matter of hours, and these systems can also be used to produce difficult-to-express proteins and antibodies.
Their open nature also enables high-throughput production and direct manipulation of the chemical environment.
Sino Biological’s cell-free platform has enabled the successful production of proteins and antibodies that are traditionally difficult to express in other systems while also maintaining shorter lead times—factors that are key to accelerating customers’ research and development processes.
The company’s cell-free platform can enable the expression of antibody fragments, such as VHH and scFv, in three hours. Using this platform, purified antibodies can be achieved in 24 hours, with high purity and binding activity comparable to antibody fragments expressed in mammalian cells.
A broad range of antibody formats
Sino Biological’s customers benefit from the company’s many years of experience working with IgGs, dimeric IgAs, multivalent IgMs (pentameric or hexameric), antibody fragments, and bispecifics.
Beyond IgGs
In recent years, the scientific research and drug development community have shown increased interest in antibody isotypes other than IgG. For example, IgM and IgA antibodies exhibit increased avidity, reduced T-cell toxicity, and improved accessibility to mucosal compartments compared to traditional IgGs.
These new antibody isotypes can also be utilized as new modalities of engineered antibodies.
Recombinant IgM and IgA production is more challenging due to low expression and less efficient purification. Process optimization is, therefore, vital for specific projects. Sino Biological efficiently optimizes the production of its customers’ IgM and IgA antibodies, ensuring the consistent delivery of high-purity products.
Antibody fragments
Sino Biological’s proven proficiency has allowed the company to successfully complete a number of antibody fragment production projects. Its multiple expression platforms, including HEK293, CHO, and cell-free systems, afford Sino Biological a range of experience in the production and purification of a wide and varied array of antibody fragments, including monovalent formats like Fab, scFv, and VHH, and bispecific constructs.
Bispecific antibodies
The manufacture of bispecifics presents several challenges, primarily due to their complexity. Sino Biological provides a rapid and efficient bispecific antibody production service based on its proprietary mammalian cell expression platforms, enabling the rapid discovery and development of bispecific therapeutics.
Beginning with antibody sequences, Sino Biological can deliver a wide range of bispecific antibody formats, including BiTE, IgG(H)-scFv, Diabody, CrossMab, DVD-IgG, and DutaMab.
New US-based center for bioprocessing
With its headquarters in Beijing and subsidiaries in Europe, the United States, and Japan, Sino Biological boasts more than 900 employees, serving researchers in academia and industry worldwide.
Sino Biological announced the formal opening of its new Center for Bioprocessing (C4B) in Houston, Texas, in October 2023. This announcement marked a major milestone in the company’s global presence, with its new center specializing in CRO services such as custom recombinant protein and recombinant antibody development and manufacture.
The C4B is evidence of Sino Biological’s ongoing commitment to its global CRO capabilities, expanding the company’s already robust CRO service offering at its Beijing headquarters.
The C4B team is committed to delivering high-quality custom recombinant proteins and antibodies and is ready to work alongside researchers and industry leaders to forge a brighter future in the global life sciences sector.
Future outlook
The field of recombinant antibodies has an exciting future. It is anticipated that ongoing growth in the cell, gene, and mRNA therapy markets will prompt continued expansion of the recombinant antibody sector. These fields are already intimately linked, and will likely merge in the future.
The field must continue to advance and researchers continue to ask questions. Continuous inquiry is key to gaining more information on the potential of recombinant antibody technology, while also increasing understanding of its various aspects.
Sino Biological is confident that this continual exploration will lead to compelling answers, including novel technologies that can underpin the discovery, development, and production of novel recombinant antibodies with the potential to improve patient lives.
References and further reading
- Zhang, C. (2012). Hybridoma Technology for the Generation of Monoclonal Antibodies. Methods in Molecular Biology, 901, pp.117–135. https://doi.org/10.1007/978-1-61779-931-0_7.
- Mitra, S. and Tomar, P.C. (2021). Hybridoma technology; advancements, clinical significance, and future aspects. Journal of Genetic Engineering & Biotechnology, [online] 19(1), p.159. https://doi.org/10.1186/s43141-021-00264-6.
- Zeng, X., Shen, Z. and Mernaugh, R. (2011). Recombinant antibodies and their use in biosensors. Analytical and Bioanalytical Chemistry, 402(10), pp.3027–3038. https://doi.org/10.1007/s00216-011-5569-z.
- Gray, A.C., et al. (2016). Animal-Friendly Affinity Reagents: Replacing the Needless in the Haystack. Trends in Biotechnology, 34(12), pp.960–969. https://doi.org/10.1016/j.tibtech.2016.05.017.
- Peltomaa, R., et al. (2021). Recombinant antibodies and their use for food immunoanalysis. Analytical and Bioanalytical Chemistry, 414(1), pp.193–217. https://doi.org/10.1007/s00216-021-03619-7.
- Wilkinson, I., et al. (2021). Fc-engineered antibodies with immune effector functions completely abolished. PLOS ONE, 16(12), p.e0260954. https://doi.org/10.1371/journal.pone.0260954.
- Reddy, S.T., et al. (2021). Optimization of therapeutic antibodies by predicting antigen specificity from antibody sequence via deep learning. Nature Biomedical Engineering, 5(6), pp.600–612. https://doi.org/10.1038/s41551-021-00699-9..
- Abd-Alrazaq, A., et al. (2020). Artificial Intelligence in the Fight against COVID-19: A Scoping Review (Preprint). Journal of Medical Internet Research, 22(12). https://doi.org/10.2196/20756.
- Kuwahara, A., Kazunori Ikebukuro and Asano, R. (2023). Protein engineering of antibody fragments for pharmaceutical production. Applied Physics Reviews, [online] 10(3). https://doi.org/10.1063/5.0158032.
- Cuesta, Á.M. et al. (2010) 'Multivalent antibodies: when design surpasses evolution,' Trends in Biotechnology, 28(7), pp. 355–362. https://doi.org/10.1016/j.tibtech.2010.03.007.
- Nuñez-Prado, N., et al. (2015). The coming of age of engineered multivalent antibodies. Drug Discovery Today, 20(5), pp.588–594. https://doi.org/10.1016/j.drudis.2015.02.013.
- Deyev, S.M. and Lebedenko, E.N. (2008). Multivalency: the hallmark of antibodies used for optimization of tumor targeting by design. BioEssays, 30(9), pp.904–918. https://doi.org/10.1002/bies.20805.
- Lu, R.-M., et al. (2020). Development of Therapeutic Antibodies for the Treatment of Diseases. Journal of Biomedical Science, 27(1), pp.1–30. https://doi.org/10.1186/s12929-019-0592-z.
Acknowledgments
Produced from materials originally authored by Suranjana Sen, Ph.D. from Sino Biological.
About Sino Biological Inc.
Sino Biological is an international reagent supplier and service provider. The company specializes in recombinant protein production and antibody development. All of Sino Biological's products are independently developed and produced, including recombinant proteins, antibodies and cDNA clones. Sino Biological is the researchers' one-stop technical services shop for the advanced technology platforms they need to make advancements. In addition, Sino Biological offer pharmaceutical companies and biotechnology firms pre-clinical production technology services for hundreds of monoclonal antibody drug candidates.
Sino Biological's core business
Sino Biological is committed to providing high-quality recombinant protein and antibody reagents and to being a one-stop technical services shop for life science researchers around the world. All of our products are independently developed and produced. In addition, we offer pharmaceutical companies and biotechnology firms pre-clinical production technology services for hundreds of monoclonal antibody drug candidates. Our product quality control indicators meet rigorous requirements for clinical use samples. It takes only a few weeks for us to produce 1 to 30 grams of purified monoclonal antibody from gene sequencing.
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