FIG. 2.

Quantitation of NiV envelope glycoprotein-mediated cell fusion. HeLa cells were infected with recombinant vaccinia viruses encoding either NiV F, NiV G, both NiV F and G, neither (none), or both HeV F and G, along with a recombinant vaccinia virus encoding T7 RNA polymerase (effector cells). Each designated target cell type was infected with the reporter vaccinia virus vCB21R, encoding E. coli lacZ. NiV or HeV glycoprotein-expressing cells (10⁵) were mixed with each target cell type (10⁵) in duplicate wells of a 96-well plate. After 3 h at 37°C, Nonidet P-40 was added and β-Gal activity was quantitated. Key: target cells only, level of background β-Gal activity in target cell populations alone; none, β-Gal activity from target cells mixed with HeLa partner cells infected with T7 RNA polymerase-encoding vaccinia virus only and no recombinant vaccinia viruses encoding NiV or HeV glycoproteins. The level of background β-Gal activity in effector cell populations alone is labeled “effector cells” on the x axis. (A) Species tropism of NiV-mediated cell fusion. (B) NiV-mediated cell fusion, compared to HeV-mediated fusion, with human T-cell and neuroblastoma cell lines.