Fig. 3

Polyomavirus infection in cortex and white matter by immunohistochemistry and electron microscopy. a-b Immunostaining with the cross-reacting polyomavirus antibody anti-SV40 T-Antigen shows strong nuclear positivity in cortical neurons, predominantly in layers II-V (a) and in scattered enlarged oligodendroglial and astrocytic nuclei (b) in the white matter. c-d Immunoreactivity with the cross-reacting antibody anti-VP1 capsid protein is absent in cortical neurons (c) but is present in scattered cells with glial appearance in the white matter (d). e Electron micrographs reveal a neural cell with aggregates of spherical particles admixed with chromatin (arrow), scale bar = 5 μm. f At higher power, 30–40 nm in diameter non-enveloped icosahedral viral particles are observed, focally forming sheets and paracrystalline arrays (arrow); scale bar = 0.26 μm