RT-PCR verification of selected cytokine gene expression levels. Pooled lung RNA samples used for microarray analyses were used for RT-PCR of CCL9, Msr1, CCL17, MMP12, and β-actin. Signals for these genes from 9 V/null and WT lung RNAs were normalized to β-actin RNA. The average values (fold changes) for RT-PCR (hatched bar) represent the ratios of 9 V/null and WT at each time point (X-axis). The fold change values were from 2 separate triplicate experiments. The comparative fold changes (Table 1) for each respective gene from the microarray analyses are shown as grey bar.