2. Materials and methods
2.1. Virus and cells
The cytopathogenic HM-175 strain of HAV (ATCC VR-1402) was
propagated and assayed in confluent FRhK-4 cells (courtesy of Prof.
Albert Bosch, University of Barcelona). Semi-purified stocks were obtained
from infected FRhK-4 cells by three freeze–thaw cycles after
8–11 days post-infection. Cell debris was pelleted at 660 ×g for
30 min. Infectious viruses were quantified by determining the 50% tissue
culture infectious dose (TCID50) with eight wells per dilution and
20 μl of inoculum per well (Pintó et al., 1994).
2.2. Reagents
Viability dyes, propidium monoazide (PMA) and ethidium
monoazide (EMA), were purchased from Geniul (Spain). Both reagents
were dissolved in 20% dimethylsulfoxide (DMSO) at 2 mM and stored at