Fig. 3

Cell death in LACV-infected iPSC-derived human COs. a A resazurin reduction-based cell viability assay was performed daily on individual COs within a 24 well plate. Data is plotted as an average percent of base fluorescence measured at 590 nm for each CO just prior to infection with mock (open circles) or LACV (closed squares). Fluorescence for each sample at each time point was read in triplicate at the indicated time point. A two-way ANOVA with a Sidak’s multiple comparisons test was used to determine significance. *p < 0.05, **p < 0.001. Data are representative of n = 3 mock and n = 6 LACV 10³ COs. b–d Representative images of COs immunohistochemically labeled for active caspase-3 (Casp3, magenta), LACV (green), and nuclei (blue). b is from a mock-infected CO, c a 3 dpi LACV-infected organoid and d a 6 dpi LACV-infected organoid. Scale bar in d also applies to b and c. e, f High magnification images taken from the same section of a 3 dpi LACV-infected CO. e Illustrates a caspase3⁺ cell (magenta) that is infected with LACV (green). f Caspase3⁺ cells that are not infected with LACV (white arrows) and LACV-infected cells that are not caspase3⁺ (yellow arrows). Scale bar in f also applies to e