Stability of IL-1α, IL-1β, TNF-α, and TF mRNA in plasmin-treated monocytes.

Monocytes were stimulated for 4 hours with plasmin 1.43 CTA U/mL (▪) or LPS 1 μg/mL (○). The level of the corresponding cytokine or TF mRNA at this time point was 100%. Actinomycin D (5 μg/mL) was added, and incubation continued for the indicated time. Poly(A)⁺RNA was isolated and subjected to RT-PCR. HLA(B) was used for normalization; its stability over 4 hours was not significantly different in controls than in plasmin- or LPS-treated cells. Results are the mean ± SEM of 3 independent experiments. Curves were fitted by least-squares regression analysis and were used to calculate the half-life of each mRNA species.