Fig. 3.

Antiviral activity of nelfinavir and GNA. At 15 h postinfection, CPE foci were counted under an inverted microscope. (A) Reduction of CPE foci in FCoV-infected cells following treatment with nelfinavir or GNA. (B) Nelfinavir significantly blocked the induction of CPE foci only at the highest concentration tested, whereas GNA showed strong inhibitory activity in a concentration-dependent manner. Statistical analyses of antiviral activity were performed using Student's t-test. **P < 0.001, compared with positive control. PC, positive control; NC, negative control. All samples were analyzed in triplicate.