To address whether direct interaction of mouse CD11bϩ cells with d7EB cells was required for the shift to anti-inflammatory lung cytokine profile observed in mice in the cell transplantation group, lung CD11bϩ cells were isolated from septic mice 12 hours after CLP and cocultured with d7EB cells either directly or indirectly via separation using a 0.4-L Transwell microporous filter. Both direct and indirect co-cultures were stimulated with LPS for 6 hours, and the supernatants were analyzed for TNF-␣ and IFN-␥ production using a mouse-specific Tissues were snap-frozen, cut into 5-m sections, and examined for native fluorescence at confocal microscopy. Nuclei have been counterstained with DAPI. Magnification ϫ40. Image is representative of at least 3 experiments. C: d7EB-conditioned medium has no effect on sepsis-induced mortality. In contrast to d7EB transplanted cells, conditioned medium from d7EB cells injected 1 hour after CLP did not prevent death. In this experiment, 2.5 ϫ 10 6 d7EB cells in 1 ml of medium were stimulated or not stimulated in vitro with LPS, 1 g/ml, for 12 hours. The supernatant was collected, centrifuged to remove any cells, and injected i.v. in mice 1 hour after CLP at a volume of 200 L per mouse. The two control groups received an equal volume of either DMEM/F-12 growth medium not exposed to d7EB cells or sterile PBS. N ϭ 25 in each group. ELISA. Only direct co-culture reduced TNF-␣ and IFN-␥ production by the CD11bϩ cells ( Figure 4D ).