Lipopolysaccharide (LPS) induces dendritic cell (DC) maturation and fascin production. T-cell activation by DCs depends on formation of an immune synapse (IS). Ligand-induced activation of LXR in DCs inhibits the LPS-induced expression of fascin, an actin-bundling protein that promotes actin bundle formation and is essential for IS formation. By this means, LXR agonists prevent efficient T-cell activation as indicated by diminished proliferation, decreased expression of activation markers (CD25, CD69), and decreased cytokine production (eg, IL-2).