Next-Generation DNA Sequencing of VH/VL Repertoires: A Primer and Guide to Applications in Single-Domain Antibody Discovery

Immunogenetic analyses of expressed antibody repertoires are becoming increasingly common experimental investigations and are critical to furthering our understanding of autoimmunity, infectious disease, and cancer. Next-generation DNA sequencing (NGS) technologies have now made it possible to interrogate antibody repertoires to unprecedented depths, typically by sequencing of cDNAs encoding immunoglobulin variable domains. In this chapter, we describe simple, fast, and reliable methods for producing and sequencing multiplex PCR amplicons derived from the variable regions (VH, VHH or VL) of rearranged immunoglobulin heavy and light chain genes using the Illumina MiSeq platform. We include complete protocols and primer sets for amplicon sequencing of VH/VHH/VL repertoires directly from human, mouse, and llama lymphocytes as well as from phage-displayed VH/VHH/VL libraries; these can be easily be adapted to other types of amplicons with little modification. The resulting amplicons are diverse and representative, even using as few as 103 input B cells, and their generation is relatively inexpensive, requiring no special equipment and only a limited set of primers. In the absence of heavy-light chain pairing, single-domain antibodies are uniquely amenable to NGS analyses. We present a number of applications of NGS technology useful in discovery of single-domain antibodies from phage display libraries, including: (i) assessment of library functionality; (ii) confirmation of desired library randomization; (iii) estimation of library diversity; and (iv) monitoring the progress of panning experiments. While the case studies presented here are of phage-displayed single-domain antibody libraries, the principles extend to other types of in vitro display libraries.