AJP January 2011, Vol. 178, No. 1 in CD11bϩ cells isolated from the lungs of septic mice 12 hours after CLP, where decreased expression of the enzyme was again observed ( Figure 5E ). To further test the hypothesis that NO production by d7EB cells contributes to the anti-inflammatory phenotype of the mouse CD11bϩ cells, an NO donor (DETA NONOate) was added directly to LPS-stimulated CD11bϩ cells, this time without d7EB cells, at concentrations ranging from 0.5 to 2 mol/L, and cytokine concentrations in the supernatant were measured. Reduction in TNF-␣ and IFN-␥ production by the LPS-stimulated CD11bϩ cells was observed ( Figure 5F ). In addition, iNOS expression in these cells after stimulation with LPS was reduced to levels comparable to those observed after co-stimulation with human d7EB cells ( Figure 5G ).