Massively-multiplexed epitope mapping techniques for viral antigen discovery

Abstract

Following viral infection, viral antigens bind specifically to receptors on the surface of lymphocytes thereby activating adaptive immunity in the host. An epitope, the smallest structural and functional unit of an antigen, binds specifically to an antibody or antigen receptor, to serve as key sites for the activation of adaptive immunity. The complexity and diverse range of epitopes are essential to study and map for the diagnosis of disease, the design of vaccines and for immunotherapy. Mapping the location of these specific epitopes has become a hot topic in immunology and immune therapy. Recently, epitope mapping techniques have evolved to become multiplexed, with the advent of high-throughput sequencing and techniques such as bacteriophage-display libraries and deep mutational scanning. Here, we briefly introduce the principles, advantages, and disadvantages of the latest epitope mapping techniques with examples for viral antigen discovery.

Keywords: B cell; T cell; epitope; epitope mapping; phage-display.

Figure 1

Multiplexed serology for viral epitope mapping. Top left: Alanine Scanning-Deep Mutational Scanning (DMS) of dsDNA to generate multiple epitope variants. Top right: peptide/protein arrays with hundreds/thousands of proteins spotted onto glass array slides and quantified by fluorescent antibody binding. Bottom right: bacteriophage display library, such as Virscan, generating single bacteriophage with single peptides, then quantified via NGS sequencing post-immunoprecipitation. Bottom left: p-MHC loaded multimers screened in a similar way to display libraries, coupled to NGS of attached DNA barcodes for epitope identification.