FIG. 2.

Quantitation of apoptosis in M. avium subsp. paratuberculosis-infected bovine monocytes stained with Hoechst 33342. Prior to infection, the monocytes were incubated overnight with 10 ng of BGH per ml (open bars) or with medium alone (negative control) (shaded bars). The monocytes were then infected with 10⁶ CFU of live or heat-killed (hk) M. avium subsp. paratuberculosis (PTB) per ml. Additional monolayers of uninfected monocytes were treated with 500 nM staurosporine (Stauro) (positive control) or left untreated (negative control). The results are the mean and standard error of the mean of four experiments, using monocytes from four different donor cattle.