Characterization of a chimeric foot-and-mouth disease virus bearing a bovine rhinitis B virus leader proteinase

Bovine rhinitis B virus (BRBV) shares many motifs and sequence similarities with foot-and-mouth disease virus (FMDV). This study examined if the BRBV leader proteinase (L-pro) could functionally replace that of FMDV. A mutant A(24)L(BRV)3D(YR) FMDV engineered with the BRBV L-pro and an antigenic marker in the 3D polymerase exhibited growth properties and eIF4G cleavage similar to parental A(24)WT virus. The A(24)L(BRV)3D(YR) type I interferon activity in infected bovine cells resembled that of A(24)LL virus that lacks L-pro, but this effect was less pronounced for A(24)L(BRV)3D(YR) infected porcine cells. In vivo studies showed that the A(24)L(BRV)3D(YR) virus was attenuated in cattle, and exhibited low virulence in pigs exposed by direct contact. The mutant virus induced protective immunity in cattle against challenge with parental A(24)WT. These results provide evidence that L-pro of different Aphthoviruses are not fully functionally interchangeable and have roles that may depend on the nature of the infected host. Published by Elsevier Inc.