FIG 4.

Anti-EHV-1 gC antibodies in serum before and after Ab4 challenge infection in EHV-1-susceptible and -protected horses. A total of 24 horses were challenged intranasally with neuropathogenic EHV-1 Ab4 (arrows). Horses in control/Ab4 were fully susceptible to EHV-1 infection. Horses in the previously infected Ab4ΔORF2/Ab4 and Ab4/Ab4 group were protected from disease. EHV-1 gC-specific antibodies were quantified in serum by fluorescent bead-based multiplex assays. Total Ig (A), IgG1 (B), IgG4/7 (C), IgG3/5 (D), and IgM (E) were measured and are shown as median fluorescent intensity (MFI). Mean and standard errors are plotted for each group. Significant differences between groups are marked as a (control/Ab4 versus Ab4ΔORF2/Ab4) and b (control/Ab4 versus Ab4/Ab4).