FIG 6.

Recovery of recombinant hMPVs carrying mutations in the RGD motif. (Top) Immunostaining spots formed by recombinant hMPVs. LLC-MK2 cells were infected with recombinant hMPV mutants and incubated at 37°C for 1 h. At day 4 postinfection, the supernatant was removed and cells were fixed. The cells were then labeled with an anti-hMPV N protein primary monoclonal antibody, followed by incubation with HRP-labeled rabbit antimouse secondary antibody. After incubation with AEC chromogen substrate, positive cells with immunostaining spots were visualized under a microscope. (Bottom) Plaque morphology of recombinant hMPVs. An agarose overlay plaque assay was performed in monolayer Vero E6 cells. Viral plaques were developed at day 7 postinfection.