Figure 4.

SARS-CoV production by alveolar type II cells. Type II cells were cultured at an A/L and inoculated with SARS-CoV, as described in Materials and Methods. (A) Cells were processed for the extraction of RNA and real-time quantitative RT-PCR at 6 and 24 hours after virus inoculation to measure SARS-CoV–specific viral RNA. For this series of experiments, six different donors were used, and all showed a significant increase in SARS-CoV mRNA at 24 hours after inoculation. (B) The production of infectious virus is shown. In this series of experiments, the yields of virus released from the apical (red) or basolateral (black) surfaces or from cell extracts (blue) at 4, 24, and 48 hours after inoculation were titered by plaque assay in Vero E6 cells and expressed as the total virus yield from each insert. The points represent the means and standard errors from four independent experiments.