FIG 3 .

ECIS identifies the growth impairments of recombinant FHV-1. (A) CRFK cells were infected with FHV-1-gD-DsRed or WT FHV-1 at an MOI of 3 or 0.01 to measure single-step (graphs i and ii) or multistep (graphs iii and iv) growth curves, respectively, with conventional viral infectivity assays. qPCR was used to quantify intracellular genomic viral DNA copy numbers, and standard plaque assays were used to quantify extracellular virus titers. (B) Normalized impedance (Z′) values of CRFK cells infected with FHV-1-gD-DsRed or WT FHV-1 at a high MOI of 3 (i) or a low MOI of 0.01 (iii). Half-maximal Z′ (Z′₅₀) values for impedance curves based on data from graphs i and iii were determined (graphs ii and iv, respectively). *, P < 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001.