FIG. 9.

NDV is a much more potent inducer of IFN-α/β than RSV in GM-CSF-cultured bone marrow-derived dendritic cells. Supernatants from infected and uninfected cultures analyzed in Fig. 8 above were assayed for IFN-α/β activity 24 h after infection. In WT mDC cultures, NDV infection induced approximately 100 times more IFN-α/β than did RSV, and this difference was even greater for IFNAR^−/− (αR-/-) DCs. When cultures (grown in FLT-3L) containing both mDCs and pDCs were infected with these viruses, very high IFN levels were produced in response to either. No IFN-α/β could be detected in any uninfected culture. Levels from RSV-infected cells are depicted by black bars, and levels from NDV-infected DC are shown in white.