FIG 7 .

CoV-induced macropinocytosis is dependent on EGFR activation. (A) Gefitinib was added to cells for 12 h, and toxicity was assessed with CellTiter-Glo. (B, C) DBT cells were mock infected or infected with MHV A59 at an MOI of 1 PFU/cell in DMEM or in DMEM supplemented with DMSO or gefitinib at 1.5 hpi. Cells were fixed at 8 hpi. Nanoparticles were added 3 h prior to fixation, and cells were washed, fixed, stained, and imaged. The percentage of cells with internalized nanoparticles (B) and the number of nuclei per syncytium (C) were determined. (D, E) DBT cells were mock infected or infected with MHV A59 at an MOI of 1 PFU/cell in DMEM or in DMEM supplemented with DMSO or EIPA at 1.5 hpi. Cells were fixed at 8 hpi, stained, and imaged. The percentage of infected cells involved in syncytia (D) and the number of nuclei per syncytium (E) were determined. Data are means ± standard deviations of triplicates. n = ≥30 fields per replicate. Statistical significance was assessed by one-way ANOVA with Dunnett’s post hoc test. ***, P < 0.0001; **, P < 0.01; *, P < 0.05.