How a research team is using cell sorting in their workflow to develop an innovative platform for synthetic antibody generation
Therapeutic monoclonal antibodies against COVID-19 virus
Monoclonal antibody (mAb) therapeutics have been available for decades, but they are costly to develop and manufacture, and development timelines are too slow to address the rapid rise of novel human pathogens such as SARS-CoV-2. This has highlighted the urgent need for rapid antiviral drug discovery platforms, leading to researchers redeveloping and updating previously established technologies to accelerate the discovery and validation of therapeutic mAbs. New integrated pipelines now combine flow cytometry, bioinformatics, synthetic biology, and high-throughput analyses.
Alon Wellner
Researchers at the University of California, Irvine (UCI) have addressed this issue by developing a synthetic antibody generation platform–based on Autonomous Hypermutation yEast surfAce Display (AHEAD) technology–for the accelerated evolution and isolation of high affinity antibody variants.1 Dr. Alon Wellner, a postdoctoral researcher in the Department of Biomedical Engineering at UCI, leads a team that focuses on developing systems for rapid discovery and engineering of affinity reagents, mostly antibodies and nanobodies. “We have combined two technologies into AHEAD that are both very powerful and successful in their own right. The first, yeast surface display, has been around for about 20 years, and is one of the most established methods in the field.”
Wellner adds, “The other technology is called orthogonal replication, which allows us to build very simple yeast cells that we can grow quickly in the lab. These cells mimic the function of B cells in that their genome is very stable, but a portion of their DNA is hypermutated, rather like how B cells mutate their antibodies and affinity mature them. The engineered yeast cells display repertoires of antibodies on their surface. Then we use cell sorting to recover the cells with the highest affinity towards the targets.”
When we first got the system, a Sony field representative came to our lab and spent three days training us. I had some experience in cell sorting and had used basic protocols, but none of the other lab members had ever done so. Sony provided very thorough training, where we discussed all the different applications that we could use for our needs.
As part of the AHEAD workflow, the team uses the Sony SH800 Cell Sorter to sort and enrich antigen-specific yeast cells of interest. The SH800 was set up three years ago, and its use in the lab has evolved since. “When we first got the system, a Sony field representative came to our lab and spent three days training us. I had some experience in cell sorting and had used basic protocols, but none of the other lab members had ever done so. Sony provided very thorough training, where we discussed all the different applications that we could use for our needs.”
“Now, when a new member joins the lab, we can train them very easily and quickly ourselves,” comments Wellner. “It typically takes just a few hours to get somebody started. Since then, we've been in contact with Sony, and they've been providing lots of support. Together, we've been developing more complicated and elaborate protocols to use within our lab.”
SH800 Cell Sorter
The team has continued to refine the workflow and has successfully overcome any challenges along the way.
The coronavirus pandemic came with its own unique set of issues, requiring the team to respond quickly to a rapidly evolving situation. “During COVID-19, we were in the unique and privileged position to tackle the virus by developing an array of antibodies that could tightly bind and neutralize the virus, preventing it from being able to enter human cells. Using rapid cell sorting, we developed a set of eight very potent antibodies that proved to be highly effective.”
“The technology proved itself during the pandemic,” according to Wellner, “since we were able to scale up our efforts and produce a potent neutralizing cocktail that could bind different epitopes of the spike protein. In the future, we believe that this technology–which has since been upgraded to be much faster and stronger in its mutagenic capacity–can be very beneficial for providing a rapid response against emerging pathogens.”
References
- Wellner A, McMahon C, Gilman, MSA, et al. Rapid generation of potent antibodies by autonomous hypermutation in yeast. Nat Chem Biol. 2021;17:1057-1064. DOI