Normal human lung fibroblasts differently modulate interleukin-10 and interleukin-12 production by monocytes: Implications for an altered immune response in pulmonary chronic inflammation

The ability of lung fibroblasts to modulate the immune response has been evaluated by analyzing the synthesis and release of interleukin (IL)-10 and IL-12 by lipopolysaccharide (LPS)-stimulated peripheral blood monocytes exposed to pulmonary fibroblast conditioned medium (FCM). IL-10 and IL-12 contents and gene expression were markedly modified by treatment with FCM as measured by ELISA ( + 97.5 ± 12.8% and –68 ± 7.3% for IL-10 and IL-12, respectively), immunocytochemistry, and reverse transcriptase–polymerase chain reaction (RT-PCR). These effects appeared to be mediated by prostaglandin E2 (PGE2) as the modified release of both cytokines was reduced by treatment with indomethacin and mimicked by addition of exogenous PGE2. As a result of the enhanced production of IL-10, exposure of LPS/interferon (IFN)- γ –activated monocytes to FCM was also able to reduce the expression of the class II major histocompatibility complex (MHC) molecule, human leukocyte-associated antigen-DR (HLA-DR) ( − 51.8 ± 8.7%) and ...