FIG 8.

Experimental paradigm and cellular response to PRV infection in rat brain. (A and B) Paradigm. Injection of the PRV Bartha strain into the interpositus nucleus of the rat cerebellum (A) resulted in retrograde spread of virus to infect neurons within the inferior olive (B). The brown reaction product visible in panel B represents immunocytochemical localization of viral antigens marking infected cells within the inferior olive and surrounding brain stem 2 days after injection of virus. (C) Thick section. The panel is a toluidine blue-stained 1-μm section from the boxed area shown in panel B. Intensely basophilic cells define reactive glia in relation to infected neurons. (D to G) Thin sections. Processing of tissue adjacent to the thick section for TEM analysis revealed infected neurons (n) and reactive astrogliosis (ast) within the cerebellum. Because the number of astrocytes was so large, some are labeled internally with an asterisk. Several infected neurons exhibited vacuolization and were intimately associated with reactive glial cells and their processes. Marker bars for panels D to G are 6 μm.