The E2 glycoprotein is necessary but not sufficient for the adaptation of classical swine fever virus lapinized vaccine C-strain to the rabbit.
Li Y, Xie L, Zhang L, Wang X, Li C, Han Y, Hu S, Sun Y, Li S, Luo Y, Liu L, Munir M, Qiu HJ.
Virology. 2018 May 4;519:197-206. doi: 10.1016/j.virol.2018.04.016
Abstract
Classical swine fever virus (CSFV) C-strain was developed through hundreds of passages of a highly virulent CSFV in rabbits. To investigate the molecular basis for the adaptation of C-strain to the rabbit (ACR), a panel of chimeric viruses with the exchange of glycoproteins Erns, E1, and/or E2 between C-strain and the highly virulent Shimen strain and a number of mutant viruses with different amino acid substitutions in E2 protein were generated and evaluated in rabbits. Our results demonstrate that Shimen-based chimeras expressing Erns-E1-E2, Erns-E2 or E1-E2 but not Erns-E1, Erns, E1, or E2 of C-strain can replicate in rabbits, indicating that E2 in combination with either Erns or E1 confers the ACR. Notably, E2 and the amino acids P108 and T109 in Domain I of E2 are critical in ACR. Collectively, our data indicate that E2 is crucial in mediating the ACR, which requires synergistic contribution of Erns or E1.