Expression of P2X7R confers to DC-derived microvesicles susceptibility to ATP-dependent lysis and triggers IL-1β release. Immature DCs were stimulated with 200 μM BzATP in sucrose saline solution and the expression of P2X7R (A), P2Y2R (B), and CD39 (C) were analyzed by Western blot both in untreated cells (DCs) and in microvesicles released (ves) after stimulation with 200 μM BzATP. The expression of MHC II (D) was also detected in microvesicles from immature (Imm) and mature (Mat) DCs. HEK-293 transfected with P2X7 cDNA and HEK293 wild type were used as positive and negative controls for P2X7R expression, respectively; human lymphocytes (Lymph) were used as positive control for CD39 expression. Panel E shows IL-1β content of intact microvesicles (⊡), microvesicles lysed by freeze thawing (□), or microvesicles treated with 3 mM ATP at 25°C for 20 minutes (▪). Data are averages ± SE of 3 experiments performed with cells from 3 different donors.
