Expression of Fas and FasL mRNA in anti-CD3–activated 3DO cells in the presence of anti–IL-2 neutralizing MoAb. (B) Northern blot. Total RNA was extracted, separated on agarose gel (20 μg/line), and transferred to nitrocellulose filter. The filter was hybridized with a nick-translation–labeled Fas cDNA probe, washed, and exposed for autoradiography. (A) RNase protection analysis of FasL mRNA expression. The protected antisense mRNA FasL fragment is 184 bp. Each line was loaded with 20 μg of total RNA. 1, Control; 2, anti-CD3–treated cells; 3, anti-CD3 + anti–IL-2 control isotype-treated cells; 4, anti-CD3 + anti–IL-2 treated cells.