From bispecifics and ADCs to better reagents

Image courtesy of Vector Labs

Widespread antibody sequencing and recombinant expression techniques have revolutionized therapeutic antibody development. However, these same innovations are now transforming basic research, setting a new gold standard for high-quality, reproducible antibody reagents. By leveraging sequencing, engineering and expression strategies refined in the biopharmaceutical industry, scientists can generate antibodies with superior qualities to hybridoma-derived or polyclonal antibodies.

These advances allow for the creation of bispecific, ‘Fc-silenced,’ and other specialized antibody reagents tailored to specific research needs. These engineered antibodies are deepening our understanding of complex biological systems and accelerating research that informs the development of next-generation cell and gene therapies (CGT). 

Described below are several pertinent areas where advanced antibody engineering is enhancing CGT research and development.

Adding clarity to in vitro research

Antibody engineering allows the creation of chimeric antibodies, which have proven valuable in therapeutic and research applications alike. Chimerization involves the grafting of an antibody variable region of one species onto the antibody backbone of another species. The resulting products offer many advantages for in vitro research — chimeric antibodies can facilitate multiplexing by enabling researchers to create panels of antibodies from different species which can be selectively detected by secondary antibodies. Likewise, chimerization can be used to reduce background staining mediated by strong Fc receptor binding of many antibody isotypes. 

Using Fc silencing mutations, such as those developed to reduce therapeutic antibody Fc-effector functions, can reduce unwanted staining in applications such as flow cytometry and immunofluorescence microscopy. Fc silencing and chimerization facilitate the creation of standardized, multiparametric flow cytometry panels that provide valuable insights across every stage of CGT research and development. For example, researchers leverage panels of diverse antibodies to identify and quantify potential therapeutic targets, investigate complex cytokine environments, characterize cell populations, and assess therapeutic response and persistence. In addition to supporting analytical applications, these engineered antibodies also provide a ‘cleaner’ foundation for cell sorting techniques.

Enhancing in vivo research possibilities 

Recombinant antibody engineering approaches have also dramatically impacted in vivo research informing CGT development by overcoming many of the limitations associated with anti-species immune responses in animal models. This is particularly valuable as researchers begin to explore CAR-T cell therapy in combination with immune checkpoint inhibitors, bispecific T cell engagers, and other immunotherapies. Antibodies used in combination therapy research can be engineered to minimize in vivo immunogenicity, enabling more long-term, stable use of model animals for better translational data. 

Modulating Fc effector function beyond the aforementioned Fc silencing is another valuable capability in engineering antibodies for in vivo research. Depending on the specific target, differing levels of Fc receptor binding, and the resulting cross-linking, may be preferred.

More recently, fully murine bispecific antibodies have become available, giving access to syngeneic surrogate molecules for next-generation translational research. By bringing studies in surrogate models as close to the clinic as possible with advanced, species-specific tools, we can improve the translational value of research for CAR-T cell combination therapies and beyond. 

Creating novel bioconjugate reagents

Recombinant antibody technology has broadly impacted immunoassay capabilities by increasing the consistency of antibody reagents, helping researchers overcome persistent issues with experimental reproducibility. Beyond these advantages in quality, antibody engineering technologies have further enhanced reagent performance, such as in combination with bioconjugation techniques to develop more consistent antibody-drug/label conjugates.

Traditional random conjugation results in heterogeneous labeling and variability in signal output. Incorporating reactive groups such as peptide tags or non-canonical amino acids into recombinant antibodies enables site-specific addition of fluorophores and other payloads, yielding more consistent products that facilitate accurate quantification. By improving assay sensitivity and reproducibility, site-specific labeling helps researchers gain deeper insights into disease mechanisms and cell fate and persistence, accelerating the development of safer and more effective therapies.

Advancing antibodies 

While many innovations in recombinant antibody engineering have resulted from efforts to advance antibody-based therapeutics, their impact extends far beyond these. The advent of widespread antibody sequencing and recombinant expression techniques contribute to the development of cell therapies, as well as novel combination therapies and research reagents. From comprehensive flow cytometry panels to species-matched assays, sophisticated antibody engineering techniques are helping to equip researchers at every level with powerful tools.