Preparation of virus-infection-associated (VIA) antigen of foot-and-mouth disease (FMD) virus from inactivated vaccine.

Abstract

Virus-infection-associated (VIA) antigen of foot-and-mouth disease (FMD) virus was prepared from an inactivated FMD vaccine. The VIA antigen coupled with an adjuvant of aluminium hydroxide gel supplemented vaccine was efficiently eluted by suspending and stirring in high concentration of phosphate buffer solution (0.3M, pH 7.6). The final elute purified by DEAE-Sephadex A50 from the vaccine was concentrated in 1/500-1/1,000 of the original volume. VIA antigens prepared from two kinds of vaccine (Type O and Asia-1) were antigenically identical to one prepared from a cell culture infected with live virus. Two cattle were infected with FMD virus (Type O) and sera were obtained from each cattle every week. The VIA antigens from the inactivated vaccine were compared with the ones from the cell culture infected with live virus in agar gel diffusion tests using sera from cattle infected with live virus. The antibodies against the VIA antigen were detected between the second week and the 13th or 14th week after infection. The VIA antigen from an inactivated vaccine would be very useful in FMD free countries like Japan to avoid the risk of using live FMD viruses.