Aggregation-associated loss of antigenicity observed for denatured virion protein 1 of Equine rhinitis A virus in an enzyme-linked immunosorbent assay

Equine rhinitis A virus (ERAV) is a picornavirus which causes an acute respiratory infection in horses worldwide, and virus neutralization (VN) has been the standard method for the detection of ERAV antibody in horse serum. Previous studies have identified recombinant virion protein VP1 (rVP1) purified under native conditions to be of high potential for the development of a diagnostic ERAV enzyme-linked immunosorbent assay (ELISA). This study presents an optimized protocol for the expression and purification of native full-length rVP1. Furthermore, we demonstrate that, upon denaturation, rVP1 no longer reacts to ERAV antibody in a prototype ELISA. Size exclusion chromatography (SEC) performed on native and denatured rVP1 indicates that denatured rVP1 forms multimeric aggregates that may causally connect to the loss of antigenicity observed in the ELISA.