Brought to you by Genscript ProBio
In December 2019, a third pathogenic human Coronaviruses, named 2019 novel coronavirus (2019-nCoV/SARS-CoV-2/COVID-19), was found in Wuhan, China. Until March, 2021 after it was identified, the total confirmed global cases have exceeded 120 million with more than 2.6 million deaths. The number of COVID-19 cases is still rising each day with an unprecedented speed and scale.
In the beginning of COVID-19 pandemic, vaccines as well as SARS-CoV-2 virus neutralizing antibodies which could be applied in treatment, prophylaxis, and detection are two major approaches to prevent virus transmission. GenScript ProBio has superior platforms in antibodies discovery, including hybridomas, phage displayed antibody library and single B cell screening platform. Single B cell screening and phage displayed libraries could screen antibody leads in short time and thus provide the best choice in this urgent moment.
Single B cell screening platform, a micro-chamber based platform, can be used to isolate, confine, and interrogate each individual B cells to maximize the antibody repertoires that we can access. GenScript ProBio has built our own single B cell platform, ProSpeed™ by using Beacon™, a micro-chamber based platform. To speed up the antibody discovery, each wild type mouse was received 7 doses of recombinant the receptor binding domain (RBD) of SARS-CoV-2 spike protein (S) in a total of 14 day duration.
After immunization, mice lymph nodes were harvested and processed to CD138+ cells enrichment. CD138+ antibody secreting cells (ASCs) were imported on chip for single B cell screening on Beacon™ (Berkeley Lights, CA) to identify positive single B cell clones that secrete RBD binding antibodies and block RBD binding ACE2 (Angiotensin-converting enzyme 2) overexpressing stable cell line at the same time. 93 RBD binders and blocker were identified and 65 recombinant IgG were successfully sequenced and produced. 65 leads were narrowed down to 23 clones with more than 40% FACS blocking ability. Then, 23 antibody leads were examined the SARS-CoV-2 pseudovirus neutralization ability (Figure 1).
Figure 1:
Among those 23 antibody leads, all of them showed better potency than virus ligand ACE2-Fc fusion protein. The IC50 of SARS-CoV2 pseudovirus neutralization antibodies ranges from 70.6 pM to 2.729 nM (Figure 2).
Figure 2. Neutralizing capacity of SARS-CoV-2 neutralizing antibody leads screened by Genscript Probio’s ProspeedTM
Figure 1. SARS-CoV-2 neutralizing antibodies screening by GenScript ProBio’s ProspeedTM
Figure 2:
In summary, through single B cell platform (GenScript ProBio’s ProSpeed™) and Express immunization, it took only 8 weeks from immunization to functional recombinant antibody protein. Unlike hybridomas and phage displayed library which screen binder and then test functions as well as sequencing, GenScript ProBio’s ProSpeed™ screens antibody leads by function in the front.
Combined with high-throughput sequencing by next generation sequencing, antibody leads for protein production could be narrowed down according to sequence clustering. To accelerate therapeutics development, human antibody transgenic animal combined with GenScript ProBio’s ProSpeed™ is highly recommended.
GenScript ProBio is now the certified CRO of Ligand’s Omni-rodent, Alloy Therapeutic’s ATX mice, and CAMouse in China. GenScript ProBio provides the best antibody discovery platforms and make therapeutics development faster and more efficient.
Expedited timeline
Screen the most B cells before losing them
Intrinsic advantage for challenging targets
