Fig 6.

PirB expression does not dictate reovirus infection patterns in the brain. (A–D) Two-to-three-day-old WT or PirB^-/- mice were inoculated IC with phosphate-buffered saline (mock) or 200 PFU of reovirus strain T3SA−. Mice were euthanized at 7–8 days post-inoculation, and brain tissue and whole blood were collected. (A) Titers of the virus in the homogenized left-brain hemisphere and blood were determined by plaque assay. Each symbol represents the viral titer from an individual animal. Brain, N = 28/27 (WT/PirB^-/-); blood, N = 31/35 (WT/PirB^-/-). Error bars indicate SEM. Values that differ significantly from WT by unpaired t test are indicated (*P < 0.05). Dotted line indicates limit of detection. (B–D) Right-brain hemispheres (with contralateral hemisphere viral load between 4.17e⁸ and 1.4e¹⁰) were fixed in formalin, embedded in paraffin, and sectioned sagittally. Tissue sections were probed for reovirus RNA by HCR, counterstained with Hoechst dye, and imaged using a Lionheart FX automated imager. (C) Representative images are shown. Reovirus RNA is depicted in green; nuclei are depicted in blue. Scale bar, 1,000 µm. (C and D) Reovirus infection in established ROIs. Infection foci (HCR-positive) from each region (C) or subregion (D) of mock-infected and reovirus-infected mouse sections were enumerated using the Spot Detector tool within Icy software. Data are presented as the percentage of infected cells, wherein a reovirus-positive cell was determined by signal intensity greater than background defined using a mock-infected brain. N = 7/9 (WT/PirB^-/-). Error bars indicate SEM. Values that differ significantly from WT by Sidak’s multiple comparisons test are indicated. DPall, dorsal pallium; MTt, collicular midbrain tectum; MPall, medial pallium; PH, pontine hindbrain; PPH, prepontine hindbrain; Th, thalamus; Thy+PHy, hypothalamus; and SPall, subpallium.