Recombinant antibody technology has been leveraged to mitigate a range of common problems associated with hybridoma platforms, helping to facilitate the development of an entirely new class of biologic drugs.
This technology continues to significantly contribute to drug development today, most notably to discovering and developing new antibody-based therapeutics and enhancing the performance of novel modalities.
Drivers of the recombinant approach
Early monoclonal antibody (mAb) therapies were developed mainly via the hybridoma platform, which necessitates the production of the target antigen or immunogen and the use of animal immunizations.
There are apparent ethical issues with the hybridoma technology, and it suffers from problems around antibody heterogeneity, batch-to-batch variability, loss of antibody productivity, and limitations in terms of cost and scale.
This process is also extremely time-consuming, often taking several months from initial immunization to establishing specific hybridoma clones and the resulting mAb production.1,2
Recombinant antibodies are generated from host cell lines through recombinant DNA technology. This approach significantly reduces the need for animal testing while enabling 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 and can be precisely replicated. Production of these antibodies is also highly controlled, consistent, and reproducible.5 Recombinant antibodies offer a range of other benefits, including the ability to target hybridoma-refractory antigens and good amenability to antibody engineering.
Engineering advantages
Recombinant antibody engineering affords researchers and drug developers a wide range of opportunities for creating unique molecules with attributes ideally suited to the treatment of specific diseases.
For example, it is possible to modify the fragment crystallizable (Fc) region to prevent the initiation of any undesired responses, while tiny variable regions can also be designed to bind to the target more effectively.6 Antibodies initially discovered in mice or other animals can then be humanized to reduce any potential immunogenicity.
Years of experience working within this area of drug development inspires confidence around the changes required to realize specific benefits; and as artificial intelligence (AI) algorithms continue to improve, this predictability and confidence will only increase.
Several drug developers are already leveraging AI technologies in the prediction and analysis of potential therapeutics from antibody sequences, using algorithms to assess their potential before production has commenced.7,8
With these predictions in place, high-throughput recombinant antibody production and characterization processes are employed in the wet lab to validate these predictions and further expedite drug discovery and development.
Platform processes are also available, enabling the rapid upscaling of recombinant antibody production to meet rising clinical and commercial demand.
Understanding fragments
A key benefit of recombinant antibody technology is its potential for exploring and characterizing many types of mAbs, a potential only limited by the imagination.
Recent years have seen increased use and prevalence of engineered antibody fragments employed as biopharmaceuticals, including monovalent formats like Fab, scFv, and VHHl; and bispecific constructs such as BiTE and Diabody.
Traditional mAbs exhibit some limitations in clinical applications; however, immunoglobulin G (IgG) molecules are comparatively large (~150 kDa), often hindering their effective penetration into tissues. The presence of the Fc region in the IgG molecule can also mediate bystander activation of the immune system.
It is important to note, however, that antibody fragments retain the targeting specificity of intact mAbs and exhibit properties that make them ideal for use in a range of therapeutic and diagnostic applications.
Their small size makes antibody fragments well suited to tissue penetration, affording them reduced immunogenicity and the ability to bind to traditionally inaccessible epitopes.
These fragments offer structural flexibility and are relatively simple to produce and engineer. They can also serve as building blocks for a range of novel constructs.
Extensive expertise is required to effectively produce and purify antibody fragments, especially considering their increased design complexity and diversification over recent years.
Several factors should be carefully considered when working with antibody fragments, including the implementation of appropriate design strategies, the use of upstream production processes to ensure high productivity while suppressing the generation of impurities, and the nature of any downstream processing requirements needed to produce the desired fragment in a sufficiently pure form.9
Modifications for research, diagnostic, and therapeutic applications
Biomedical research applications necessitate antibodies that can penetrate different tissues to properly assess different molecular and behavioral characteristics. In this case, antibody fragments offering better tissue penetration than full-length IgG are a popular choice.
Diagnostic applications will favor engineered multivalent antibodies with enhanced antigen-binding avidity.10,11,12
Therapeutic applications, however, tend to work with recombinant antibodies as these can be modified in many ways to achieve any number of characteristics. For example, they can be modified to target effector cells more strongly, avoid cross-reactivity, or enable site-specific conjugation to small molecule payloads.
The unlocked potential of recombinant antibodies
There is great interest in the therapeutic possibilities offered by cell and gene therapies and other novel modalities. However, it is also recognized that recombinant antibodies still offer significant development potential.
Their ability to enable targeted therapies with minimal side effects means that recombinant antibodies will continue to play a key role in developing treatments for various human diseases, such as cancers, autoimmune diseases, metabolic diseases, and infectious diseases.13
Next-generation antibody therapeutics such as mAbs, bispecifics, antibody fragments, and antibody-drug conjugates exhibit novel functionalities, offering even greater targeting abilities and improved efficacy.
From a diagnostic perspective, recombinant antibodies facilitate the highly selective and sensitive detection of specific biomarkers at several different disease stages, allowing for more tailored treatments focussed around disease progression.
Upcoming innovations in targets and modifications
It is anticipated that the recombinant antibody sector will continue to increase in size and scope to include novel targets and modifications. As the field develops deeper insight into genomic and proteomic changes in diseases, new targets have emerged for which no currently available antibody drugs exist.
It is also important to note that a considerable gap exists between target discovery and the development of a corresponding therapeutic antibody. Recombinant antibodies are seeing more medical applications due to their precise design, powerful engineering, and efficient production. Their ongoing development is especially important due to the pressing need to develop antibodies for a range of novel entities.
Any given target or application will benefit from a greater understanding of the design landscape, investigating a range of known and unknown opportunities, and identifying the best possible engineering steps. These steps ensure optimal affinity, specificity, and other properties.
Major advances are expected in the near future, with developments in the field that will revolutionize the recombinant antibody sector and result in antibody therapies becoming available for unknown targets.
The role of recombinant antigens and antibodies in the COVID-19 pandemic response
The COVID-19 pandemic saw a tragic worldwide loss of life, but this period also highlighted several positive aspects of the biopharma industry that are normally not widely considered.
Sino Biological was active throughout the pandemic, producing research reagents, providing contract research services for biopharmaceutical companies, and working alongside the diagnostic industries to further advance vaccines, therapeutics, and immunodiagnostic assays related to the SARS-CoV-2 virus.
Since then, the company has created a comprehensive collection of recombinant antigens and antibodies for SARS-CoV-2, supporting scientists' research worldwide. This work has led to more than 2,000 publications to date.
The pandemic necessitated a rapid response, requiring Sino Biological to work extremely fast in developing reagents and implementing contract research services.
In January 2020, the company produced key SARS-CoV-2 spike protein reagents in a record time of just 11 days, and in December 2021, it developed the Omicron RBD protein in a new record time of just six days.
These products were developed and manufactured using Sino Biological’s proprietary recombinant platforms.
Since the COVID-19 outbreak, the company has been actively tracking changes in the virus and investigating new variants to ensure its products are as up-to-date as possible. It is also continually working to ensure that its SARS-CoV-2 reagent portfolio covers all variants of interest (VOIs) and variants under monitoring (VUMs).
Sino Biological has developed ProVir®, the world's biggest and most comprehensive viral antigen bank. This bank contains antibodies for almost all of these viral antigens and antibody pairs with high specificity and sensitivity.
These antibody pairs are especially important due to their roles in therapeutic, vaccine, and diagnostic research in areas such as influenza, COVID-19, RSV, and many other fields of immunology and virology.
Tailoring supply to meet client requirements
The biopharmaceutical industry collaborates with contract research organizations (CROs) to produce custom antibodies. These relationships allow the industry to leverage CROs’ access to advanced technologies, specialized expertise, and established platforms to mitigate risks, reduce costs, and save time.
Recombinant technology offers more possibilities and the flexibility to tailor production according to precise needs. It also represents an ideal solution to the ever-increasing complexity and diversification of antibody-based biopharmaceuticals, which have driven the outsourcing trend further.
Conversations around outsourcing to a CRO generally begin with discussions around the end application. With this established, a review of the target antigen is conducted, exploring any specific requirements that will impact the antibody's design, engineering, and production against the target.
The goal is always to ensure best-fit strategies, generating high-performing antibodies with the right properties for the target applications. The approach to this will vary and depends mainly on what the client seeks to achieve.
Sino Biological: Building on over 15 years’ of recombinant antibody expertise
Recombinant technology has been used at Sino Biological since its early development, leveraging this to generate catalog protein and antibody products throughout its highly regarded contract development and manufacturing business.
The company continues to fine-tune and advance its capabilities in both these areas, leading Sino Biological to become a key partner to several COVID-19 therapy and vaccine developers and continuing to provide custom services for organizations developing diagnostic products and novel therapies.
A plethora of platforms
Sino Biological maintains a comprehensive suite of expression platforms to meet its customers' diverse needs. These platforms cover a range of applications, from fast and efficient cell-free to cell-based systems, such as mammalian cell and baculovirus-insect cell expression systems.
Mammalian cell expression
Producing recombinant proteins and antibodies from mammalian cells offers various advantages to clinical studies or human research. Mammalian cells can manufacture a protein or antibody that mimics nature, ensuring the molecule's proper posttranslational modifications are executed.
Sino Biological's highly optimized mammalian cell expression platforms can accommodate proprietary culture media, expression vectors, transfection reagents, supplements, and boosters.
The company’s high-throughput platform can accommodate over 1,000 projects simultaneously, ranging from genes to recombinant antibodies for discovery and screening purposes.
A customer can receive over 1,000 different antibodies from Sino Biological in only two weeks, and product availability on scales ranging from micrograms to kilograms means that the company’s global customer base receives precisely the quantity of consistent, high-quality products they require.
Cell-free synthesis
Cell-free systems facilitate the rapid production of proteins and antibodies in vitro without using living cells. Protein and antibody synthesis in cell-free systems generally takes only a few hours.
Cell-free systems also allow for the production of difficult-to-express proteins and antibodies, while their open nature is central to the potential for high throughput and the direct manipulation of the chemical environment.
Sino Biological’s proven cell-free development platform has successfully produced proteins and antibodies that have been historically challenging to express in other systems with shorter lead times. In these instances, the cell-free development platform has been instrumental in accelerating customers’ research and development processes.
The company’s cell-free platform can express antibody fragments scFv and VHH in three hours. Purified antibodies can also be achieved in just one day while ensuring high purity and binding activity comparable to antibody fragments expressed in mammalian cells.
A wide range of antibody formats
Sino Biological’s many years of experience working with IgGs and expertise with dimeric IgAs, multivalent IgMs (pentameric or hexameric), bispecifics, and antibody fragments can benefit customers.
Beyond IgGs
As well as IgG, many other antibody isotypes have begun to garner attention in scientific research and drug development circles. For example, IgM and IgA antibodies have exhibited lower T cell toxicity, higher avidity, and improved accessibility to mucosal compartments versus traditional IgG.
IgM and IgA antibodies can be employed as new modalities of engineered antibodies, but recombinant IgM and IgA production poses a greater challenge due to low expression and less efficient purification.
Therefore, process optimization is imperative for projects working with these antibodies. Sino Biological is adept at optimizing the production of customers’ IgM and IgA antibodies, ensuring the consistent delivery of high-purity products.
Antibody fragments
Sino Biological has completed numerous antibody fragment production projects, demonstrating proficiency in each instance and leveraging its thorough experience in producing and purifying diverse antibody fragments.
The company offers multiple expression platforms, including HEK293, CHO, and cell-free systems, and has experience working with monovalent formats, such as scFv, Fab, VHH, and bispecific constructs.
Bispecific antibodies
Bispecifics’ high complexity represents a specific manufacturing challenge. Sino Biological provides fast and efficient bispecific antibody production services based on its proprietary mammalian cell expression platforms, an ideal solution for the rapid discovery and development of bispecific therapeutics.
Sino Biological can deliver a wide range of bispecific antibody formats from initial antibody sequences, including IgG(H)-scFv, Diabody, CrossMab, BiTE, DVD-IgG, and DutaMab.
A new United States-based center for bioprocessing
Sino Biological is headquartered in Beijing, China, and the company has subsidiaries in Europe, the United States, and Japan. It employs over 900 staff and serves researchers in industry and academia worldwide.
In October 2023, Sino Biological formally announced the opening of its new Center for Bioprocessing (C4B) in Houston, Texas, marking a key milestone in the company’s global presence. This new bioprocessing center specializes in CRO services, including developing and manufacturing custom recombinant proteins and antibodies.
The C4B represents the ongoing global expansion of Sino Biological’s CRO service capabilities, expanding upon the company’s robust existing CRO offering at its Beijing headquarters.
The expanded and increasingly global team remains committed to delivering high-quality, custom recombinant proteins and antibodies. Sino Biological looks forward to partnering with international researchers and industry leaders to forge a brighter future in the life sciences sector.
Future outlook
There is a great deal of excitement and optimism about the future of recombinant antibodies. Growth in the gene, cell, and mRNA therapy markets will continue to enhance the recombinant antibody sector, with these intimately linked fields expected to merge eventually.
However, it is important to remember that there is always room for improvement in any sector. Both industry and academia must keep asking questions because continuous inquiry leads to more information and increases overall understanding of recombinant antibody technology and its many facets.
Sino Biological believes this ongoing exploration will lead to compelling answers and novel technologies that further facilitate the discovery, development, and production of novel recombinant antibodies that can improve patient lives.
References and further reading
- Zhang, Chonghui. “Hybridoma Technology for the Generation of Monoclonal Antibodies.” Methods in Molecular Biology. 901: 117–135. (2012).
- Mitra, Sanchita and Pushpa C. Tomar. “Hybridoma technology: advancements, clinical significance, and future aspects.” J. Genet. Eng. Biotechnol. 19: 159 (2021).
- Zeng, Xiangqun, Zhihong Shen, and Ray Mernaugh. “Recombinant antibodies and their use in biosensors.” Anal. Bioanal. Chem. 402: 3027–3028 (2012).
- Gray, A.C. et al. “Animal-Friendly Affinity Reagents: Replacing the Needless in the Haystack.” Trends in Biotechnology. 34: P960–969 (2016).
- Peltomaa, Riikka et al. “Recombinant antibodies and their use for food immunoanalysis.” Anal. Bioanal. Chem. 414: 193–217 (2022).
- Wilkinson, Ian et al. “Fc-engineered antibodies with immune effector functions completely abolished.” PLoS One. 21 Dec. 2021.
- Mason, Derek M. et al. “Optimization of therapeutic antibodies by predicting antigen specificity from antibody sequence via deep learning.” Nature Biomedical Engineering. 5: 500–612 (2021).
- Abd-Alrazag, Alaa et al. “Artificial Intelligence in the Fight Against COVID-19: Scoping Review.” Journal of Medical Internet Research. 15 Dec. 2020.
- Kuwahara, Atsushi, Kazunori Ikebukuro, and Ryutaro Asano. “Protein engineering of antibody fragments for pharmaceutical production.” Applied Physics Reviews. 7 Sep. 2023.
- Cuesta, Angel M. et al. “Multivalent antibodies: when design surpasses evolution.” Trends Biotechnol. 28: 355–362 (2010).
- Nuñez-Prado, Natalia et al. “The coming of age of engineered multivalent antibodies.” Drug Discov. Today. 20: 588–594 (2015).
- Deyev, Sergey M. and Ekaterina N. Lebedenko. “Multivalency: the hallmark of antibodies used for optimization of tumor targeting by design.” Bioessays. 30: 904–918 (2008).
- Lu, Ruei-Min et al. “Development of therapeutic antibodies for the treatment of diseases.” Journal of Biomedical Science. 2 Jan 2020.
Acknowledgments
Produced from materials originally authored by Dr. Suranjana Sen 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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