FIG. 5.

Localization of viral antigen in brain sections. Animals were inoculated intranasally with either BHV-5Us9R or BHV-5Us9Δ as described earlier (14, 28). The animals were euthanatized on 4, 6, 8, 10, and 13 dpi or when they showed neurological signs, and their brains were processed for immunohistochemical analysis as described earlier (28). On the left is shown a low-power montage of Nissl-stained sections that indicate the locations of the micrographs shown on the right (indicated by boxes). Representative sections of the anterior olfactory nucleus (A), piriform cortex (B), and amygdala (C) are pictured. In this assay, BHV-5Us9R spread to the anterior olfactory nucleus, piriform cortex, amygdala, and hippocampus (not shown) at 8 dpi; no labeling was observed in BHV-5Us9Δ virus-infected animals at 4 to 13 dpi.