Regulation of IL-12R β2 subunit mRNA expression by IFN-γ. FACS^®-sorted naive CD4⁺ DO11.10 T cells were cultured with OVA peptide and irradiated BALB/c splenocytes under conditions indicated. On day 5 after primary antigen activation total cellular RNA was isolated from the developing Th cells. Sequential Northern blot analysis was performed using as probes the full-length murine IL-12R β2 subunit cDNA (top), the full-length murine IL-12R β1 subunit cDNA (middle), and the GAPDH cDNA (bottom).