Figure 2.

(a and b) Immunofluorescence micrographs of cell surfaces of Vero C1008 and Vero 76 cells stained with anti-Udorn antisera and FITC-conjugated rabbit anti-guinea pig Ig. Note the intense cell surface staining of Vero 76 cells but lack of filamentous particles (a), whereas filamentous particles (arrows) are budding from infected Vero C1008 cells (b). (c and d) Electron micrographs of negatively stained virus released from BHK-21 cells or HEC-1 cells. Filamentous particles were frequently observed in the virus released from HEC-1 cells (d) but spherical or slightly elongated particles were produced by BHK-21 cells (c). (a and b = ×500; c and d = ×3,800.)