Figure 7. Neutralization of IFN-β protects cells from apoptosis.

BMDM were prepared from B6.C3H-sst1 mice. Where indicated (panel a, c and d), cells were primed with IFN-γ (10 U/ml). Cells were incubated with neutralizing Ab against IFN-β (panel d) or isotype control (panel c) at a final concentration of 250 ng/ml 6 hr prior to infection with Cp (MOI 3∶1). At 10 hpi, cells were fixed and stained using the TUNEL assay. A: fluorescent images showing TUNEL positive cells (green); cells are counterstained with DAPI (blue). B: Quantified data from fluorescent images shown in A are graphed as the percent TUNEL positive cells. The small letters (a–d) in image A correspond to the bars shown in graph B below. Significance: ***, p≤0.001.