Eosinophil apoptosis and the activation of p36 MBPK is attenuated by catalase.

Eosinophils were aged for 24 hours in the absence or presence of the Fas-activating antibody, CH-11 (100 ng/mL), together with the indicated concentrations of catalase. The percentage of apoptotic cells (mean ± SEM of 3 independent determinations) was then enumerated by PI-labeling of DNA fragmentation (A). Kinase activity was measured by “in gel” renaturation assays using MBP as a substrate. A representative autoradiograph obtained from 3 independent experiments is shown in B. C indicates control cells at 0 hours. P versus no catalase: * < .05 and ** < .01.