TNF- and tumor cell supernatant exert suppressive effects in vitro on the expression of selected genes by BAEC. Confluent BAEC were cultured for 8 hours either without (C) or with 1 nmol/L TNF- (TNF) and/or with lymphoma cell conditioned supernatant (TS). The mRNA expression was detected by Northern blot analysis for the genes A4, B2, C3, and E10. The autoradiograms depicted below the histograms were quantitated by densitometry as described in the legend to Fig 1 and in Materials and Methods. Histograms for the calculated relative densitometry units (y-axis) for the single genes are shown. The bar graphs represent different treatments. The differences seen between C and the TNF + TS group were significant (P = .015, Wilcoxon rank sum test).