Figure 4.

TLR3 ligands induce an early IFN type I release and a late increase in IL-8 levels. A, B) MSCs (nmMSCs or bmMSCs) were stimulated with 1 μM Poly I:C and SNs were collected at 4 h, 8 h and 24 h poststimulation. Levels of IL-8 (A) and IFN type I (B) were determined as above. C, D) MSCs were continuously stimulated with 1 μM Poly I:C for 4 or 24 h. In addition, Poly I:C was washed away after 4 h, fresh medium was added, and the cells were allowed to release cytokines for another 20 h (4–24 h). Levels of IL-8 (C) and IFN type I (D) in the SNs were assessed as above. Cytokine levels induced by Poly I:C at 4 h poststimulation were considered as 100%. Data are means ± sd of 3 independent donors.