Fig. 3: Mechanism of immunogenic cell death induced by the autolysing SDV system.

a Illustration depicting the IASNDS system invading GBM cells, triggering cell death, activating antigen-presenting cells, and eliciting an immune response. b IASNDS cellular entry, intracellular autocleavage initiation, and tumor cell pyroptosis induction mechanism. c Transmission electron microscopy characterizing the structures of the SDVs and IASNDS, highlighting SLINs coupled to the IASNDS surface (white arrow). (n = 3 independent experiments). d GFP release from SDVs into the cytoplasm (green, black arrow) and the presence of lysed Salmonella membranes inside cells (red, white arrow) after coculture of 1 × 10^6 CFU of the IASNDS with QL01#GBM cells for 48 hours (n = 3 independent experiments). e Detection of the GFP fluorescence intensity inside tumor cells after coincubation of 1 × 10^6 CFU of the IASNDS with QL01#GBM cells for 48 hours (n = 9 images from three independent experiments). (exact P value: P = 2.491E−12); ****P < 0.0001. f, g Intratumor cell fluorescence intensity over 24 hours in QL01#GBM cells, illustrating IASND intracellular release behavior (n = 9 images from three independent experiments). (exact P value: P = 7.8029E-11); ****P < 0.0001. h Altered cell membrane permeability and cytoplasmic efflux post IASNDS treatment of QL01#GBM cells (green, white arrow), along with dispersed bacterial membranes after SDV cleavage (red, black arrow). (n = 3 independent experiments). Data are presented as the mean ± S.D. The statistical comparisons in e was performed with two-tailed, unpaired Student’s t tests, with asterisks indicating significant differences. c, d, f, and h are representative images of the corresponding independent biological samples. The scale bars in c are 150 nm (middle) and 50 nm (bottom), the scale bar in d is 0.5 μm, and the scale bars in f and h are 1 μm. Source data are provided as a Source Data file.