FIG 10.
Viral RNA of all variants is present in CSF, but ependymal cells are efficiently infected only by reference virus rOC/ATCC. Twenty-two-day-old C57BL/6 mice received 101.5 TCID50/10 μl of rOC/ATCC, rOC/SG758R, rOC/SR903A, or PBS by the i.c. route. (A) RNA of each virus was quantified by qRT-PCR at 3 and 5 dpi in CSF of C57BL/6 mice after i.c. injection. Every symbol represents one single infected mouse. (B to D) Histological examination of virus spread after 5 dpi. (B) rOC/ATCC; (C) rOC/SG758R; (D) rOC/SR903A. Sections of brains were stained with MAb against the S viral glycoprotein (green). Blue is DAPI, which stains the nucleus (DNA). Left images represent lateral ventricles (white arrows) and surrounding region in mouse brain (magnification, ×10), and right images represent higher magnification (63×) of ependymal cells surrounding ventricles seen in immunofluorescence and bright field, respectively.