['Paraoxonase 1 (PON1) was suggested to play an anti-inflammatory role. In the present study we questioned whether PON1 has a direct impact on macrophage inflammatory responses, and the possible functional implications of such effects.', 'Ex-vivo studies were performed with bone marrow-derived macrophages (BMDM) harvested from C57BL/6 and human-PON1 transgenic (PON1-Tg) mice, and for the in\xa0vitro studies the J774.A1 macrophage-like cell line was used. Pro-inflammatory (M1) activation was induced by LPS and INFγ. The spontaneous and M1-induced TNFα and IL-6 secretion were significantly reduced in BMDM derived from PON1-Tg vs. C57BL/6 mice. In\xa0vitro, PON1 dose-dependently attenuated both the spontaneous and M1-induced TNFα and IL-6 secretion, and contributed to the anti-inflammatory activity of HDL. Functionally, PON1 attenuated M1-induced production of reactive oxygen species (ROS), phagocytosis, and necrotic macrophage death. PON1 anti-inflammatory activity was mediated, at least in part, via binding to SR-BI, but was independent of the enzyme catalytic activity or of cholesterol efflux stimulation, and did not involve binding to ABCA1.'] Does paraoxonase 1 ( PON1 ) reduce macrophage inflammatory responses?