Fig. 2.

Intranasal cytokine secretion after infection with EHV-1 strain Ab4 or its deletion mutant Ab4ΔORF2. Three groups of horses (n = 8/group) were either not infected (control), infected with the neuropathogenic EHV-1 strain Ab4 (Ab4) or infected with its ORF2 deletion mutant (Ab4ΔORF2) on day 0 (arrow). Before (day − 1) and after (day 1–24) experimental infection IFN-α (a), sCD14 (b), IFN-γ (c), and IL-10 (d) were quantified in nasopharyngeal secretions by fluorescent bead-based assays. Mean and standard errors are plotted for each group. Significant differences between groups are marked: a = Ab4 vs. control, b = Ab4ΔORF2 vs. control, c = Ab4 vs. Ab4ΔORF2