Figure 1.

Effect of specific receptor ligation on IL-12(p40) mRNA production by BMMφ. BMMφ from BALB/c mice were exposed to either IFN-γ and LPS (100 U/ml and 50 ng/ml, respectively), or erythrocytes opsonized with IgG (E-IgG), C3bi (E-C3bi), or maleylated BSA (E-ML-BSA), or latex microspheres, as indicated. 6 h after the addition of stimuli, total RNA was isolated and used to carry out competitive RT-PCR. The ratio of the intensity of competitor (upper band in each reaction) to wild-type (lower band in each reaction) for the amplification reaction was used to determine cDNA levels. cDNA was resolved on a 2% ethidium-stained agarose gel and normalized for HPRT intensities. The normalized cDNAs were then used in subsequent PCR reactions, using primers for the inducible p40 subunit of IL-12.