Visualising HMPV virus-like particles (VLPs) scanning electron microscopy (SEM). Vero cells were pCAGGS-transfected (Mock) and co-transfected with pCAGGS/F-cmyc, pCAGGS/G-FLAG, pCAGGS/M (FGM) and viewed by (A) SEM (magnification × 5,000; bar = 20 μm), the presence of prominent filamentous projections of the surface of FGM-transfected cells is highlighted (white arrows). (B and C) Mock-transfected and FGM-transfected cells were stained using anti-FLAG and anti-IgG conjugated to 10nm colloidal gold and viewed under field emission SEM. (B) (magnification × 20,000; bar = 1 μm) and (C) magnification ×100,000; bar = 100 nm). The distribution of gold particles (white spots) on the filaments is shown (white arrows). The images are superimposed images obtained using the secondary electron scatter and backscatter electron detectors. (D) Filamentous projections formed on HMPV-infected cells. At 7 days post-infection HMPV-infected LLCMK2 cells were stained using anti-G and examined at a focal plane corresponding to the cell periphery and cell top. The filamentous staining pattern is indicated (white arrows).