Figure 4.

Interleukin-10 (IL-10) inhibits lipopolysaccharide (LPS)-induced maturation. Dendritic cells (DC) were generated by culture with granulocyte–macrophage colony-stimulating factor (GM-CSF) + IL-10 for 8 days. Subsequently, cells were washed and cultured overnight with GM-CSF + IL-10, GM-CSF + LPS, or GM-CSF + IL-10 + LPS. (a) On day 9, the stimulated cells were incubated for 4 hr with brefeldin A, then stained for cell-surface major histocompatibility complex (MHC) class II and intracellular IL-12 and analysed by two-colour flow cytometry. (b) Graded numbers of day 9 DC, exposed overnight to GM-CSF + IL-10, GM-CSF + LPS, or GM-CSF + IL-10 + LPS, were cocultured with purified C57Bl/6 CD4⁺ T cells in an allogeneic mixed leucocyte reaction (allo-MLR). T-cell proliferation was determined after 4 days by measuring the incorporation of [³H]thymidine. Representative examples of two experiments are shown.