RSV infectivity pattern and cellular damage in HEp-2 cells visualized by immunofluorescence micrographs. Representative epifluorescence deconvolution micrographs of HEp-2 cells labeled or nuclei (DAPI), RSV (M2-1; red), and Actin (green). Cells were either mock-treated or infected with RSV/A/Tracy (GA1), RSV/A/Ontario (ON), RSV/B/18537 (GB1), or RSV/B/Buenos Aires (BA) at a multiplicity of infection of 0.01 for 24, 48, 72, or 96 h. Scale bars indicate 10 μm.