CHME-5 cells were seeded at high density on 10-cm Petri dishes and stimulated with IFN-γ, IL-4 (20 ng ml−1, 24 h), lipopolysaccaride (LPS) (100 ng ml−1, 24 h), or LPS (100 ng ml−1, 24 h) + ATP (1 mM, 30 min). Untreated cells were used as negative control. Cell supernatants were then collected and processed according to the above protocol of differential ultracentrifugation. The content of IL-1β in MVs was assessed by using the human IL-1β/IL-1F2 DuoSet ELISA Kit (R&D), according to the manufacturer’s instructions.