FIG 5.

Evaluation of the viral replication dynamics in the brain using IFA. Two-day-old mouse brains were stained for the viral antigen (SADS-CoV NP, red) and microglial cell antigen (CD68, green) at 1 (A and E), 3 (B and F), 5 (C and G), and 7 (D and H) dpi. The viral antigen (orange arrows) has been detected since 3 dpi, and a low level of microglial cell antigen (cyan arrows) was detected at 7 dpi. Images were acquired using a Pannoramic MIDI system. Infected mouse brain tissues were homogenized in DMEM and used to infect Vero cells. Compared to mock-infected cells (I and K), a cytopathic effect (CPE) (J) was observed and viral antigens (L) were detected in infected cells. Images were acquired using an Olympus FV1200 confocal microscope. Scale bars: 1000 μm (A to D), 100 μm (E to H), and 200 μm (I to L).