FIG. 2.

gB-gH/gL interaction can be blocked with gB-neutralizing antibodies from FR1. Immunofluorescence of nectin-expressing cells transfected with gL and EYFP-tagged gB (Bc) and gH (Hn). Twenty hours posttransfection, cells were incubated 1 h with 100 μg/ml MAb. Fusion was triggered with 250 μg/ml soluble gD306. Cells were fixed and examined with a confocal microscope at 100× magnification. In the absence of gD, no fusion and no BiMC was detected. Soluble gD306 triggers fusion and BiMC in the absence (b) or in the presence (c) of nonneutralizing antibody DL21. Neutralizing antibodies (d and e) block EYFP restoration and fusion. N, number of syncytia from a representative experiment; numbers are from one coverslip per sample. (f) Quantification of fusion (luciferase assay). No ab, no antibodies.