Application of Next Generation Phage Display technology to study cross reactivity in closely-related Flavivirus species

Flaviviruses are a large family of viruses, some members of which cause human and veterinary disease and pose a potential risk of death. The transmission route is typically through the bite of arthropods such as ticks or mosquitoes and. They are a major cause of emerging and re-emerging viral infections. One of the major issues faced when carrying out serology diagnostics is the risk of cross reactive antibodies among closely related species. Next Generation Phage Display is a molecular biology technique combines phage display with next generation sequencing. A phage library is created by inserting peptide sequences into a phagemid vector. Each phage in the resultant library displays a particular peptide on its external surface and the resultant phagemid is packaged within the phage particle. The main advantage of phage display is linking the phenotype (peptide binding properties) with genotype (the peptide gene within the phagemid) Serum antibodies from flavivirus infected species are immobilised on a solid support and incubated with the phage library. Following washing steps to remove non-specific binding, the phage are rescued and propagated in bacteria. This process is called biopanning and is repeated up to 4 times. The phage genomes are sequenced using Ion Torrent sequencing and through analysing the sequences, the antigenic peptide regions can be identified. The most antigenically potent sites can then be used to create a diagnostic assay such an ELISA.