Abstract:
Identifying antigenic proteins and mapping their epitopes is important for the development of
diagnostic reagents and recombinant vaccines. B-cell epitopes of African horse sickness virus
(AHSV) have previously been mapped on VP2, VP5, VP7 and NS1, using mouse, rabbit and
chicken monoclonal antibodies. A comprehensive study of the humoral immune response of
five vaccinated horses to AHSV-4 antigenic peptides was undertaken. A fragmented-genome
phage display library expressing a repertoire of AHSV-4 peptides spanning the entire genome
was constructed. The library was affinity selected for binders on immobilised polyclonal
immunoglobulin G (IgG) isolated from horse sera collected pre- and post-immunisation with
an attenuated AHSV-4 monovalent vaccine. The DNA inserts of binding phages were
sequenced with Illumina high-throughput sequencing. The data were normalised using preimmune
IgG-selected sequences. More sequences mapped to the genes coding for NS3, VP6
and VP5 than to the other genes. However, VP2 and VP5 each had more antigenic regions than
each of the other proteins. This study identified a number of epitopes to which the horse’s
humoral immune system responds during immunisation with AHSV-4.
