NOS2 and infection: These included: gp91 knockout mice in which production of reactive oxygen species (ROS) by neutrophils is greatly reduced gp91- and inducible-nitric-oxide-synthase- (iNOS-) double-knockout mice in which both ROS and NO production is greatly reduced; chemokine CXCR2 receptor knockout mice in which neutrophil recruitment to sites of infection is greatly reduced; finally wild-type mice depleted of neutrophils by systemic administration of antineutrophil monoclonal antibody.