sentences:  NOS2 is part of an autoregulatory feedback loop, wherein an allergen or provoker stimulates inflammatory cytokine production, which in turn stimulates NO production, and NO down-regulates cytokine production.In rats, NO inhibits the granulocyte-macrophage colony-stimulating factor (GM-CSF)-mediated maturation of dendritic cells, and in humans it inhibits the TNF-alpha-mediated maturation of human dendritic cells, through cyclic GMP-dependent mechanisms.NO prolongs the ability of human dendritic cells to internalize antigens at sites of inflammation, therefore modulating the beginning steps leading to antigen-specific immune responses.