Fig. 5.

IDO1 is expressed in Caco-2 cells that are infected by HAstV1 and IDO1-deficient cells exhibit impaired differentiation. (A) Relative IDO1 expression in Caco-2 cells harvested at 1 and 6 dpp; (B) HAstV1 infection of Caco-2 cells harvested at 1 dpi and stained for IDO1 (red) and capsid (green). Infected cells expressing IDO1 (closed arrowheads) and infected cells not expressing IDO1 (open arrowheads) are indicated. WT and IDO1^−/− cells were compared by (C) relative SI expression at 6 dpp; (D) transepithelial electrical resistance at 6 dpp in transwell inserts; (E) confocal microscopy of ezrin (green), Na, K-ATPase (red) and DAPI (blue) staining, and (F) comparative infection of HAstV1 and Reovirus T1L infection with quantification at 1 dpi, and (F) comparative binding of spike-green fluorescent protein (GFP) binding. Comparisons between groups were assessed by an unpaired t-test with Welch’s correction and one-tailed p values indicated, * p < 0.05, ** p < 0.001, **** p < 0.0001. Data represent individual wells run in at least two independent experiments (B, D) or a single experiment (A, C, E, F). dpi = days post infection; dpp = days post plating; Ido1 = indoleamine 2,3-dioxygenase 1; HAstV1 = human astrovirus-1; ns = non-significant; SI = sucrase-isomaltase; WT = wild-type.