Dextromethorphan (DXM)

In the presence of Dextromethorphan, the LPS-induced expression of the costimulatory molecules in murine bone marrow-derived dendritic cells (BMDCs) is significantly suppressed. In addition, Dextromethorphan treatment reduces the production of reactive oxygen species (ROS), proinflammatory cytokines, and chemokines in maturing BMDCs that are activated by LPS. Therefore, Dextromethorphan abrogates the ability of LPS-stimulated DCs to induce Ag-specific T-cell activation, as determined by their decreased proliferation and IFN-γ secretion in mixed leukocyte cultures. DXM decreases the LPS-induced surface expression of CD80, CD83, and HLA-DR and the secretion of IL-6 and IL-12 in human monocyte-derived dendritic cells (MDDCs)