DD/RT-PCR reproducibly identifies cytokine-responsive genes in HUVEC. (A) and (B) show differential display patterns for the primer sets T11GA with decamer 11 (A) and decamer 7 (B). These represent the selection criteria we used to exclude false-positives by only pursuing bands that show reproducible differential expression on DD/RT-PCR gels. (A) and (B) show enlargements for bands that are reproducibly induced at 3, 6, and 20 hours by both TNF- and monocyte-conditioned medium, whereas they are not detectable in unstimulated cells. After cloning and sequencing, these bands were shown to represent Mn-SOD and GM-CSF, respectively. (A) also shows an unknown gene fragment that is specifically induced by TNF- but not by monocyte-conditioned medium (unlabeled arrow) and was excluded from our analysis. (C) shows confirmation of differential expression of GM-CSF using the DD-fragment as probe and a Northern blotting analysis of the same RNA sample as used for the DD/RT-PCR. The insert shows the specific hybridization signal for GAPDH as internal control for equal RNA loading.