Interferon-gamma (IFN-gamma) regulates production of IL-10 and IL-12 in human herpesvirus-6 (HHV-6)-infected monocyte/macrophage lineage.

Abstract

To determine whether HHV-6 infection induces expression and production of IL-10 and IL-12 in monocytes/macrophages, and to explore the influence of IFN-gamma on cytokine production in HHV-6-infected cells, expression and production of IL-10 and IL-12 were evaluated through reverse transcription-polymerase chain reaction (RT-PCR) and sandwich ELISA. HHV-6 infection induced the expression and the production of IL-10 and IL-12 in monocytes and THP-1 cells. Kinetic study showed that the expression of IL-12 mRNA decreased with accumulation of IL-10 mRNA. Expression and production of IL-12 were markedly increased when anti-human IL-10 MoAbs were added to the cultures, implying that endogenous IL-10 induced by HHV-6 inhibited IL-12 production. Addition of increasing concentrations of IFN-gamma to the cultures of HHV-6-infected cells enhanced the expression of IL-12 gene, while the accumulation of IL-10 mRNA was down-regulated. Determination of protein levels of IL-10 and IL-12 by ELISA also showed that IFN-gamma increased IL-12 and decreased IL-10 production. These results suggest that IFN-gamma regulates the production of IL-10 and IL-12 at transcriptional level mainly through inhibiting endogenous IL-10 production in HHV-6-infected monocyte/macrophage lineage.