*2.1. Cell Lines*

A549 cells (kind gift from G. Kochs, Freiburg), HEK293 and Vero cells (kind gifts from C. Reis e Sousa, London, UK) and A549 BVDV NPro cells (kind gift from R. Randall, St Andrews) were cultured at 37 ◦C in Dulbecco's modified Eagle's medium (DMEM), supplemented with 10% FCS and 2-mM L-Glutamine.
