<i>in vitro</i> validation of the biological properties of the IC virus.

<p>(a) Plaque morphology of parental and IC-derived WNV on Vero cells. Vero cells in six-well plates were infected with 100 PFU of parental or recombinant virus. Plaques were visualized 3 days post-infection by staining with crystal violet. Data shown are representative of two independent experiments. (b) <i>SnaBI</i> digestion profile of the 1198 bp RT-PCR (5743F–6941R) fragment amplified from parental or IC-derived WNV stocks. (Quick Load 1 kb DNA Ladder, New England Biolabs). (c) Growth kinetics of parental (P) and infectious clone (IC) viruses in Vero cells at an MOI of 1. At the indicated time post-infection, culture supernatants were collected and viral titers were determined by plaque assay on Vero cells. Error bars represent the standard deviation of triplicates. (d) Immunofluorescence with anti-NS1 antibodies on Vero cells infected at an MOI of 1 with either the parental or IC-derived WNV 3 days post-infection. Data shown are representative of two independent experiments.