Effect of inhibitors and pertussis toxin on C5a-induced IL-8 promoter-directed CAT activities. RAW264.7 cells were transfected with an IL-8 promoter-CAT construct, p-272CAT, and stimulated with 200 nmol/L of C5a after 1 hour of treatment with the transcription inhibitor actinomycin D (ActD) or the translation inhibitor cycloheximide (CHX). PTX (1 μg/mL) was added 2 hours before C5a stimulation and was present during the course of C5a stimulation. The inhibitors and PTX and relative net fold induction of CAT activities by C5a are specified at the bottom of the figure.