Fig. 4: MVA infection induces pyroptosis in THP-1 cells.

a Representative temporal profiles of secreted proteins and proteins involved in the inflammasome pathway during MVA infection. (continued Supplementary Figure. 7b). n = 2 biological replicates from independent experiments. Data are presented as mean values ± range. b Cell death assessed by lactate dehydrogenase release assay. PMA-differentiated THP-1 macrophages were treated with the indicated inhibitors and infected with MVA (MOI = 5) for 8 h. Means ± s.d. (n = 3 independent experiments) are shown. c Immunofluorescence to visualise inflammasome assembly (caspase-1/ASC speck formation). Differentiated THP-1 cells that ectopically express CARD1-GFP (THP-1C1C-GFP) were infected with MVA (MOI = 5) for 8 h in presence of caspase-1 inhibitor VX-765 (4-h infection shown in Supplementary Fig. 8). Representative micrographs show caspase-1 CARD-GFP (green), ASC immunostaining (magenta) and DAPI staining (blue). Scale bar = 100 µm. Arrowheads indicate caspase-1/ASC specks. d Quantification of cells with caspase-1 CARD-GFP specks from c. Means ± s.d. (n = 4 biological replicates from 2 independent experiments) are shown. e Immunoblot showing gasdermin D (GSDMD) cleavage is stimulated during MVA infection. Differentiated THP-1s were treated as indicated and infected with MVA (MOI = 5) for 8 h. f ratio of cleaved N-terminal fragment (arrowhead) over full-length GSDMD (indicated by an asterisk) band intensities from e. The positions of molecular mass markers in kDa are shown on the left of immunoblots. Means (n = 2 independent experiments) are shown. Significance in b and d was calculated using one-way ANOVA followed by post-hoc Dunnett’s multiple comparisons test. Source data is provided as a Source Data file.