Single-cell suspensions of CD11bϩ cells were prepared from septic mice as described above. The cells were plated in 24-well plates at a concentration of 10 6 cells in 1 ml of complete RPMI-1640 medium for 1 hour. The supernatants were removed, and fresh medium was added in the presence or absence of LPS, 100 ng/ml, plus a series of concentrations of the NO donor diethylenetriamine (DETA) NONOate for 12 hours. The range of concentrations was chosen to mimic approximately the amount of NO produced by d7EB cells as determined by direct measurements as described above. At the end of the experiment, supernatant free of cells was collected for cytokine measurements via ELISA.