Dendritic cell maturation and subsequent enhanced T-cell stimulation induced with the novel synthetic immune response modifier R-848

Agents that enhance dendritic cell maturation can enhance T-cell activation and therefore may improve the efficiency of vaccines or improve cellular immunotherapy. Previously, we demonstrated that a novel low-molecular-weight synthetic immune response modifier, R-848, induces IL-12 and IFN-alpha secretion from monocytes and macrophages. Here we report that R-848 induces the maturation of human monocyte-derived dendritic cells. Characteristic of dendritic cell maturation, R-848 treatment induces cell surface expression of CD83 and increases cell surface expression of CD80, CD86, CD40, and HLA-DR. Additionally, R-848 induces cytokine (IL-6, IL-12, TNF-alpha, IFN-alpha) and chemokine (IL-8, MIP-1 alpha, MCP-1) secretion from dendritic cells. Most significantly, R-848 enhances dendritic cell antigen presenting function, as measured by increased T-cell proliferation and T-cell cytokine secretion in both allogeneic and autologous T-cell systems. Consequently, low-molecular-weight synthetic molecules such as R-848 and its derivatives may be useful as vaccine adjuvants or as ex vivo stimulators of dendritic cells for cellular immunotherapy. (C) 1999 Academic Press.