Figure 3.

CsgA‐based assemblies activate TLR2 and induce IL‐1β secretion independently of cell death. A) TLR2‐TLR1 stimulation by CsgA assemblies. HEK‐Blue cells expressing the heterodimer TLR2‐TLR1 were exposed to nanofilaments for 16 h and activation was measured using SEAP reporter. B) J774.A1 murine macrophages were incubated for 16 h with nanofilaments and levels of IL‐1β in the supernatant were measured by ELISA. C,D) Viability of J774.A1 macrophages upon treatment with CsgA‐based nanofilaments. (C) Cells were treated with nanofilaments for 16 h and metabolic activity was measured by resazurin reduction. (D) Representative fluorescence microscopy images showing the distribution of live (green) and dead (red) J774.A1 cells after treatment with 30 µg mL⁻¹ of nanofilaments for 16 h. Scale bar: 100 µm. (A–C) n = 3 to 5 per group, data represent the mean ± S.D. and statistical significance was analyzed with a one‐way ANOVA with Tukey's multiple comparisons tests (**P < 0.01; ***P < 0.001).