In contrast, nuclear fragmentation characteristic of apoptosis was observed in only 47% of cells that were infected for 3 days and 50% of cells infected for 10 days when subsequently treated with staurosporine. Chi squared analysis indicated that this inhibition of apoptosis by the infection was highly statistically signifi cant. The effect of infection by C. pneumoniae read FAQ upon the caspase pathway in the apoptotic process was examined using immunocytochemistry techniques. SK N MC neuronal cells were infected with the AR39 strain of C. pneumoniae and incubated with 1 M staurosporine for 4 hours to induce apoptosis, then Inhibitors,Modulators,Libraries screened for apoptosis with an antibody specific for the activated form of caspase 3, in conjunction with Hoechst staining to reveal the nuclear profiles.

In the absence of staurosporine, Inhibitors,Modulators,Libraries unin fected SK N MC cells revealed a normal nuclear profile with minimal Inhibitors,Modulators,Libraries active caspase 3, whereas unin fected cells treated with staurosporine clearly demon strated the characteristic apoptotic nuclear fragmentation and activated Inhibitors,Modulators,Libraries caspase 3. In cells infected with C. pneumoniae, inclusion bodies were detected by immunolabeling with a specific anti chlamy dial antibody. In non staurosporine treated cells at 24, 48 and 72 hrs post infection, there was virtually no visual evi dence of apoptosis. In contrast, in cells infected with C. pneumoniae and treated with stau rosporine, only in the 72 hr post infection culture was there limited evidence of apop totic nuclear fragmentation and activated caspase 3. To assess whether caspase activity is inhibited by C.

Inhibitors,Modulators,Libraries pneu moniae in acute or extended stages of infection, caspase activity was quantitatively measured for uninfected cells and cells at 24, 48 and 72 hours post infection. The change in caspase 3 7 activity induced by 1 M stau rosporine is plotted in Figure 8 relative to the change observed in uninfected cells. In cells assayed at 24 hours post infection, cas pase 3 7 activity in the absence of staurosporine was slightly suppressed compared to uninfected cells, but most notably the increase in activity induced by stau rosporine was suppressed to 0. 59 0. 08 compared to staurosporine treated, uninfected cells. At longer times post infection, staurosporine induced a larger increase in activity, indicating that the infection was less inhibitory at these time points, most likely as a result of a decrease in the fraction of infected cells in the cultures at these longer infection times.

apoptosis, levels of the pro apoptotic protein Bax at the mitochondrion are increased, resulting concerning in release of cyto chrome c and subsequent activation of caspase 9 and cas pase 3. This release has been shown to be blocked upon infection with C. pneumoniae. In our studies, cas pase 3 7 activity was inhibited upon infection with C. pneumoniae, possibly resulting from inhibition of cyto chrome c release.