Single B cell antibody technology is a relatively new approach to developing monoclonal antibodies (mAbs). It offers several advantages over traditional mAb technologies, including shorter timelines, higher throughput, and compatibility with artificial intelligence (AI) powered affinity maturation. With the COVID-19 pandemic highlighting the critical importance of rapid mAb development, single B cell antibody technology is seeing increased use across multiple therapeutic areas.
Monoclonal antibodies have traditionally been produced via two main routes. Hybridoma technology involves immunizing mice or rabbits with the antigen of interest, isolating the B cells for fusion with myeloma, and panning for specific antibody clones. Although hybridoma technology is still widely used, it has a lengthy workflow and can suffer from a loss of diversity due to the limited efficiency of cell fusion.
Phage display uses a surface-bound antigen to capture phages expressing different antibody single-chain variable fragments (scFvs) from solution. Any antigen-specific phages are then eluted and amplified in E. coli for evaluation of the scFvs, with high affinity binders being converted to full-length antibodies through the addition of a constant domain. While phage display is more efficient than hybridoma technology, it produces antibodies in which the heavy and light chains are not naturally paired.
Single B cell antibody technology is a newly developed approach to mAb discovery and development. Like hybridoma technology, it begins with immunizing mice or rabbits with the target antigen. However, the splenocytes and peripheral blood mononuclear cells (PBMCs) are then harvested for fluorescence-activated cell sorting (FACS) to isolate any antibody secreting B cells.
Following FACS isolation, the B cells can be directly lysed for gene amplification. Alternatively, the B cells may be expanded in vitro and the cell culture supernatants analyzed using ELISA or FACS assays. Once any positive clones have been selected, the antibody variable genes are amplified. The antibodies are then recombinantly expressed in a mammalian cell line and fully validated.
The main advantages of single B cell antibody technology over hybridoma technology are that it has a much shorter timeline and higher throughput. And, in contrast to phage display, it yields mAbs with native heavy and light chain pairs. In addition, because single B cell antibody technology conserves the natural diversity of the antibody repertoire, it can increase the likelihood of generating mAbs to more challenging targets, such as conformational determinants, which are difficult to emulate in vivo.
One of the best ways of accessing single B cell antibody technology is through an external provider. For example, Sino Biological’s single B cell antibody discovery platform represents an end-to-end solution encompassing everything from antigen generation, immunization, and single B cell screening through to B cell cloning, antibody expression, and validation. By having all of the necessary technologies in one place, antibody discovery timelines can be reduced from months to just a matter of weeks.
At the B cell screening stage, multiple platforms are applied. These include FACS, bead-based or fluorescence resonance energy transfer (FRET) based technologies, and a single B cell antibody discovery platform known as the Berkely Lights Beacon®, which was developed to accelerate various cell processing and analysis applications, including mAb discovery.
Centered on FACS, the Beacon® uses opto-electropositioning (OEP™) technology to place individual B cells in discrete chambers for automatic screening. In a mAb discovery setting this reduces the screening process to one day, compared with one to two months using traditional hybridoma technology, and achieves significantly higher throughputs of >10,000 B cells at one time.
To further speed up the mAb discovery process, researchers can choose Sino Biological’s fast mouse immunization service. This shortens the immunization period from 8–12 weeks to 4–5 weeks and enables delivery of positive clones with greater than 99.5% monoclonality in as little as 35 days.
Figure 1. The Beacon® single B cell antibody discovery workflow
To learn more about Sino Biological’s single B cell antibody discovery platform, visit sinobiological.com