Figure 4.

Fusion activity of HRSV F with cell lines derived from various species. Cell lines derived from various species (target cells) were either transfected with pFR-Luc and mixed 24 hours later with 293T cells that had been co-transfected for 24 hours with pHRSVFOptA2 or pVPack-VSV-G and pBD-NFκB (Figs. 4A and 4B), or the target cells were transfected with pBD-NFκB and mixed 24 hours later with 293T cells that had been co-transfected for 24 hours with pHRSVFOptA2 or pVPack-VSV-G together with pFR-Luc (Figs. 4C and 4D). Cell lines derived from various species were transfected with either pFR-Luc or pBD-NFκB only as negative controls. Luciferase activity was measured 24 hours post mixing of the cell populations as described in methods and is reported as relative light units.