Figure 3
Macrophage marker upregulation in SCs and GERCs during TMEV infection. (a) Under steady-state conditions, F4/80 (green) was weakly expressed in SCs, but not in GERCs. Conversely, the SCs and GERCs migrating to the HCs during the virus infection exhibited strong F4/80 expression (green), indicating the virus-induced activation of SCs and GERCs as macrophages. (b–d) Under steady-state conditions, both Irf5 (green) (M1 marker) and Jmjd3 (green) (M2 marker) were expressed in SCs, but not in GERCs (b). Virus incubation increased the expression of Irf5 (green) and Jmjd3 (green) in the SCs, which was confirmed by double-positive (Jmjd3, green; Irf5, red) expression in SCs (c). The GERCs expressed Jmjd3 (green), but not Irf5 (green) during the virus infection (d). These findings indicate that virus-infected SCs exhibit both M1 and M2 characteristics, whereas virus-infected GERCs exhibit only M2 characteristics. (e) Virus-activated SCs and GERCs phagocytised Saccharomyces cerevisiae conjugated with Alexa Fluor 488 (white arrowheads), demonstrating the macrophage-like ability of these cell types. Scale bars, 20 µm.
