Identification of recovered recombinant viruses by fluorescent assay and plaque assay. (A) the successfully recovery of rLong was confirmed through indirect immune fluorescent assay by immune-staining with an anti-RSV G1 polyclonal antibody targeting G protein epitopes as the first antibody. (B) the recovery of rLong-∆G-EGFP was evaluated by observating under fluorescent microscope. (C) the negative control was Hep-2 cells without infected by viruses. (D-F) Plaque morphology for wild-type RSV long virus, rLong and rLong-∆G-EGFP respectively.