Caspase-8 is activated in normal mouse osteoblasts infected with S. aureus at a MOI of 75:1, or following incubation with 10 μg/ml cycloheximide (CHX). Caspase-8 enzymatic activity was analyzed 45 min following infection. S. aureus-infected osteoblasts were incubated for 45 min in the presence of increasing concentrations of anti-human TRAIL antibody (0.5 μg/ml, 1.0 μg/ml, and 2.0 μg/ml). Values are presented as the mean +/- standard deviation from three independent osteoblast cultures. Data were analyzed utilizing the Student's t-test, *,# P < 0.05.