Serology is an important tool for the diagnosis of viral infection and biosecurity surveillance. Unlike PCR and antigen tests, which only work in a narrow time window, antibodies serve as a long-lasting ‘immunological record’ that remain detectable for months or years after exposure. However, conventional serology tests are difficult to multiplex and are usually run as one test per virus, per sample. Additionally, antibodies tend to cross-react between related and sometimes unrelated viruses, which can make test results difficult to interpret.
An emerging serology technique called phage immunoprecipitation-sequencing (PhIP-Seq) [1][2] combines phage display and next-generation sequencing to enable one-pot screening of thousands of antigens. This method uses a library of overlapping peptides that span viral proteins, which could offer better resolution than whole viruses or protein antigens. PhIP-Seq also uses a standardised ‘plug & play’ workflow which can be rapidly adapted to a new target panel.
Here, we present the first use of PhIP-Seq in a veterinary application. Using foot-and-mouth disease virus as a model, we used PhIP-Seq to simultaneously profile antibody responses against a selection of structural and non-structural viral proteins. Even with a limited set of samples, we were able to identify candidate regions that were highly targeted by antibodies and exhibited partial serotype-specific reactivity. Additionally, different antibody profiles towards the non-structural proteins were observed between vaccinated and infected animals, indicating the potential utility of PhIP-Seq for DIVA (Differentiating Infected from Vaccinated Animals). This work demonstrates the capability of PhIP-Seq as a powerful technique for epitope discovery and virus serotype discrimination.
References:
[1] Larman, H. B. et al. (2011). Autoantigen discovery with a synthetic human peptidome. Nature Biotechnology, 29(6), 535–541.
[2] Xu, G. J. et al. (2015). Comprehensive serological profiling of human populations using a synthetic human virome. Science, 348(6239).