Modulation of cytokine expression in mouse dendritic cell clones

Dendritic cells (DC) play an essential role in the induction of primary immune responses; however, very little information is available on cytokine production by DC. Here we determined the cytokine gene expression profile of two immortalized DC clones, CB1 and D2SC/1, both generated from mouse spleen but differing in their activation requirements. Among the cytokines tested, only transforming growth factor-beta 1 was transcribed constitutively, but its production was detected only in D2SC/1 cells after treatment with granulocyte/macrophage colony-stimulating factor (GM-CSF). GM-CSF also promoted transcription and synthesis of interleukin (IL)-1 beta in CB1 cells that need pretreatment with GM-CSF to present major histocompatibility complex class II-restricted antigens efficiently in vitro. Lipopolysaccharide (LPS) up-regulated gene expression and induced release of tumor necrosis factor-alpha in both DC clones. In addition, LPS induced transcription of IL-1 alpha and both gene expression and synthesis of IL-1 beta in D2SC/1 cells. Interferon-gamma was ineffective in inducing cytokine gene expression, although it augmented the antigen-presentation capacity of DC, IL-4, IL-10 and IL-12 mRNA were not induced by any of the tested stimuli. The results suggest that DC have a limited cytokine gene expression pattern compared to macrophages and are heterogenous in some functional properties.