Screening With the Sub-library of Super-trillion Single Domain Ab Library
Super large library capacity enables hundreds of lead antibodies
With the trillion-level library capacity, a large amount of single domain antibodies with up to pM level affinity can be obtained for targets of different characters, including single transmembrane, multiple transmembrane proteins, cytokine, etc.
The superior humanized framework ensures drug developability
Based on the accumulated experience of over130 humanization projects of single domain antibodies and thorough investigation of the template humanized framework, single domain antibodies with up to 98% humanization degree and improved drug developability can be obtained.
Automation supports diversified cross screenings
A variety of screening strategies can be customized with different antigens, such as crossing screening with FC and his tagged antigens, with solid and liquid panning phases, with cell-expressing and protein antigens, and competition and blocking screenings. The lead antibodies can be rapidly obtained by high-throughput screenings with solid and liquid phases, and the whole process takes only several weeks.
Comprehensive validation of pharmaceutical properties with the mammalian cell expressed antibodies
The full-length lead antibodies are expressed by CHO / 293 eukaryotic expression system and purified. After systematic and comprehensive physicochemical and biochemical tests and multi-dimensional affinity kinetic tests, authentic and effective proprietary drug data can be obtained.
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Analysis of in vitro binding activity
Most of the single domain antibody candidates screened from the sub-library of ST-SDAL have excellent in vitro binding activity. As shown in Figure 1, the binding EC50 of C2 on CLDN18.2-HEK293T cells is 5.636 nm, which is equivalent to that of the control antibody. Most candidate antibodies showed better affinity than the control antibody.
Fig. 1 Binding affinity determination by FACS
In vitro and in vivo validations of the drug efficacy
As shown in Fig. 2, the candidate antibody C2 showed better cytotoxicity than the control antibody (IC50 of C2 was 0.0706 nm and IC50 of the benchmark was 0.3259 nm). As shown in Fig. 3, candidate antibody C2 showed better in vivo anti-tumor efficacy than the control antibody. In the mouse MC38 tumor model, the tumor growth inhibition rate of C2 reached 97.6%.
Fig. 2 Cytotoxicity assay on HumanCLDN18.2-HEK293T cell
Fig. 3 Tumor growth inhibition