Figure 1.

(a) IFN-β titration. HeLa cells were pre-treated for 24 h with the indicated concentrations of IFN-β. After pre-treatment, the cells were either left uninfected (right) or were infected with MPXV-Zaire at an MOI = 5 in the presence of the indicated concentrations of IFN-β (left). Infected cells were harvested 24 h p.i., and lysates were titered by plaque assay. Uninfected cells were assayed for viability using a CellTiter-Glo Luminescent Cell Viability Assay. RLU = relative light units. (b) High MOI growth curve. HeLa cells were either left untreated or were pre-treated for 24 h with 2000 U/ml of IFN-β. After pre-treatment, the cells were infected with MPXV-Zaire (MOI = 5) in the presence or absence of 2000 U/ml of IFN-β. Cells (left) and medium (right) were separately harvested at the indicated times, and lysates were titered by plaque assay. Note the different scales in the left and right panels.