Interleukin-10 relieves the inhibitory effects of interferon-gamma on normal human lung fibroblasts

Interleukin-10 (IL-10) is an important cytokine that suppresses the product ion of cytokines and chemokines by immune cells. IL-10 has been suggested t o be involved in chronic inflammatory responses including the remodeling pr ocess in the lung. We investigated the effects of IL-10 on proliferation, e xtracellular matrix and cytokine production in normal human lung fibroblast s (NHLF). Human IL-10 (hIL-10) complementary DNA (cDNA) was transfected int o NHLF using an adenoviral vector. No significant changes were observed in proliferation, fibronectin or procollagen type I production in the NHLF tra nsfected with hIL-10 cDNA. Interferon (IFN)-gamma significantly inhibited c ell proliferation and extracellular matrix production in a dose-dependent m anner. Transfection of hIL-10 cDNA significantly relieved the suppressive e ffects of IFN-gamma in NHLF. Transforming growth factor (TGF)-beta producti on was not significantly affected by either transfection of hIL-10 cDNA or the addition of IFN-gamma. The relief of the suppressive function of IFN-10 by IL-10 suggested that IL-10 is indirectly involved in the remodeling pro cess in the lung interstitium.