Effect of transcription and translation inhibitors and pertussis toxin on C5a induced IL-8 secretion. Freshly prepared PBMC (0.5 × 10⁶) were preincubated with different inhibitors for 1 hour and with pertussis toxin (PTX) for 4 hours. The cells were then stimulated with 200 nmol/L of recombinant human C5a for 2 hours. The supernatants were taken for measurement of secreted IL-8 by ELISA. The final concentration of PDTC was 10 μmol/L, the transcription inhibitor ActD was added to 5 μg/mL, and the final concentration of CHX was 10 μg/mL. PTX was added to 1 μg/mL. TNF (40 ng/mL) was used as a positive control. Data were from three separate experiments, each with duplicate measurements.