FIG 1.

PI cells were resistant to superinfection with NDV. (A) Control cells or PI cells were either mock infected or infected with rNDV-GFP at an MOI of 3. At 24 h p.i., GFP expression was monitored by GFP fluorescence. (B) Control cells or PI cells were infected at an MOI of 0.001 in triplicates, their supernatants were collected from day 0 to day 4, and titers were determined by plaque assay. (C) Control cells or PI cells were either mock infected or infected at an increasing MOI in triplicates for 3 days. The percentage of dead cells relative to mock cells is plotted as means ± standard errors of the means. Data shown are from one study representative of two independent experiments.