Time course of procoagulant activity and mRNA expression after EHV-1 infection of equine monocytes. A: Monocyte-enriched fractions of equine PBMC (5 × 105 cells) were infected with the RacL11, Ab4 or NY03 strains of EHV-1 at an MOI of 1 (left panel, n = 4) or 5 (right panel, n = 10) or treated with LPS (10 ng/mL) positive or vehicle (PBS) negative controls. Procoagulant activity was measured at 1, 2, 4 and 24 h after infection. FXa generation was below the limit of detection at all time points for the vehicle control and at 1 and 2 h after infection for all viruses at an MOI of 1 and are subsequently not shown in the left panel. The mean procoagulant activity of cells infected with all viruses or treated with LPS is significantly different than the vehicle control (p < 0.05) at all time points, with the following exceptions: 1 or 2 h after infection with all virus strains at an MOI of 1 (left panel) and 1 h after treatment with LPS (both panels). Note, results depicted in the two panels are derived from different horses and experiments. * p < 0.05 versus other virus strains (for RacL11) or all virus strains (for LPS) at the same time point. ** p < 0.05 versus Ab4 or NY03 only. † p < 0.05 versus NY03 only. B: Time course of quantitative real-time PCR analysis for TF mRNA in monocyte-enriched PBMC fractions infected with RacL11 at an MOI of 1 (left panel) or 5 (right panel) or treated with LPS (10 ng/mL) and vehicle (PBS) controls. The data is expressed as the mean ± SD log2 fold increase in TF mRNA expression relative to the vehicle-treated control at 1 h (standardized to 0) after normalization to the housekeeping gene, β2-microglobulin (n = 3–6).