Ribonuclease protection assay for cytokine mRNA synthesis by EBV-transformed MJC, JTC, and KR LCL. RNA was extracted from LCL during log-phase growth, and aliquots from 10⁶cell-equivalents were analyzed with the hCK-2 probe set (PharMingen). Lanes containing untreated probes (P) and mRNA-protected probes (MJC, JTC, and KR) are shown. Ribosomal L32 and GADPH are cellular housekeeping mRNAs. The autoradiogram was from 24 hours of exposure.