Expression of luciferase by the recombinant HeV-Luc. Vero, HeLa, HEp2 and U373 human cells were infected with various amounts of HeV-Luc. At 24 hours post infection, luciferase activity in cells was measured by lysing cells using BrightGlo reagent (Promega) and reading on a Synergy H4 microplate reader (Biotek Instruments Inc). Results represent the average of 4 independent infections with error bars representing standard deviation. All values have been normalised to uninfected cells (relative light units of 1).