With Celline, NanoTag introduced a unique proprietary technology for the time-efficient discovery of single-domain antibodies.
In a single affinity selection step, a solid support displaying the target protein is used to purify target-specific B lymphocytes isolated from a pool of PBMCs. After washing, individual B-cells presenting target-specific antibodies on their surface are selectively eluted and further processed. The genetic information containing the sequence for the displayed antibodies is extracted, amplified by RT-PCR with sdAb-specific primers, and cloned into a prokaryotic expression vector. Identified sdAb clones are finally analyzed by ELISA or target-specific functional assays. Importantly, the washing stringency and elution mode during the initial affinity selection step can be customized within a wide range of conditions. This allows for the enrichment of B cells presenting antibodies with desired properties already in this stage.
![](https://usercontent.one/wp/nano-tag.com/wp-content/uploads/2021/12/Celline-english-1024x352.png?media=1720096505)
In terms of topology, Celline is an ideal camelid sdAb discovery platform when downstream assays and technologies require sdAbs to recognize proteins presented on the surface of target cells, e.g., surface-protein directed purification of blood cells or CAR-T technologies. Celline may therefore be advantageous especially for the selection of sdAbs intended for such applications.
Celline is a single-step method and ideally suited for the time-efficient development of sdAbs. After immunization, single binders can be identified within 5-8 working days.
NanoTag is currently implementing additional steps rendering the selection process specific to camelid B cells presenting camelid heavy-chain antibodies (IgG2/3 isotypes), which are the precursors of single-domain antibodies.