A megadiverse naive library derived from numerous camelids for efficient and rapid development of VHH antibodies

The field of antibody development is under pressure to meet rising demands for speed, cost-effectiveness, effi-cacy, reliability, and large-scale production. It is costly and time-consuming to immunize animals and build a single-domain antibody (sdAb) library for each target. Using the variable domain (VHH) of heavy-chain only antibodies (HcAbs) derived from blood samples of 75 non-immunized camelid animals (51 alpacas, 13 llamas, 11 Bactrian camels), and spleens from two Bactrian camels, a naive sdAb library with extensive megadiversity and reusability was constructed. The library was evaluated using next-generation DNA sequencing (NGS) and was found to contain hundreds of billions of unique clones. To confirm the availability of target-specific VHHs, a naive library was screened for a variety of targets. At least two VHH candidates were extracted for each target using a 20-day selection pipeline. Some binders had ultrahigh potencies, with binding affinities in the nanomolar range. This naive library, in particular, offers the possibility of acquiring unique antibodies targeting antigens of interest with low feasible dissociation constant (kD) without the time, effort, and price associated in producing antibodies in animals via antigen injection. Overall, the study shows that the megadiverse naive library provides a rapid, adaptable, and easy platform for antibody creation, emphasizing its therapeutic and diagnostic implications.

Automated summary

This study demonstrates the construction and application of a megadiverse naive sdAb library derived from non-immunized camelid animals. The library provides a rapid and adaptable platform for antibody creation, yielding high-affinity VHH candidates with therapeutic and diagnostic implications.