Figure 4.

Modulation of cytokine mRNA expression by rhIL-16. (a, c) Kinetics of IL-13 and IL-5 mRNA expression in PBMC incubated in the presence or absence of allergen extract for the indicated times. (b, d) IL-16 down-regulates IL-13 and IL-5 mRNA expression in allergen-stimulated PBMC harvested on day 4. Representative results of RT–PCR products for IL-13 and IL-5 mRNA are shown for allergen-stimulated PBMC under the conditions indicated. Normalization by equivalent β-actin gene expression at subsaturating cycle number is depicted for each condition. The amplified cDNA fragments have the expected lengths of 336 bp for IL-13, 271 bp for IL-5, and 417 bp for β-actin. One representative of four independent experiments is shown.