Fig. 7

The presence of cell-free virus particles occurs late in infection and correlates with increased cell permeability and cytotoxicity. HEp2 cell monolayers were infected with RSV using an multiplicity of infection of 0.0002 and (a) between 1 and 5 days post-infection (dpi) the cell-associated virus infectivity (solid line) and the cell-free virus infectivity (broken line) in the tissue culture supernatant was measured by plaque assay. Average values (duplicates) for the infectivity measurements are shown and for all times the standard error for each of the infectivity measurements was ≤ 10 %. Representative data obtained from one experiment is shown. b Lactate dehydrogenase (LDH) release from RSV-infected HEp2 cells. HEp2 cell monolayers were either mock-infected (broken line) or RSV-infected (solid line) using a multiplicity of infection of 0.0002 and at between 1 and 5 dpi the levels of LDH was measured in the tissue culture supernatant. The values are average values of triplicate measurements at each time point. Representative data from one experiment is shown