TABLE 2.

FC-10696 IC₅₀s and SI₅₀s for live MARV egress at 48 h and 72 h^a

Cell type	48 h			72 h
	CC50 (μM)	IC50 egress (μM)	SI50 egress	CC50 (μM)	IC50 egress (μM)	SI50 egress
HeLa	0.49	0.042	11.7	0.39	0.003	130
Human macrophages	4.8	0.18	26.7	4.2	0.055	76.4

^aCytotoxic properties of FC-10696 were tested in either HeLa cells or human macrophages using a CellTiter-Glo kit 48 or 72 h after treatment to select nontoxic concentration range for antiviral tests. In the virus tests, cells were challenged with MARV at an MOI of 0.01 for 1 h and then incubated with new medium containing serially diluted concentrations of FC-10696. To assess virus egress, cell supernatants were titrated on Vero cells. Infected cells were detected by staining with anti-MARV VLP antibody, and nuclei were stained with Hoechst dye. Samples were subsequently imaged and analyzed. The concentration that reduced cell viability by 50% (CC₅₀) and the half-maximal inhibitory concentration (IC₅₀) for virus egress were determined by nonlinear regression analysis. The selectivity index (SI₅₀) was calculated as CC₅₀/IC₅₀.