Monophosphoryl lipid A activates both human dendritic cells and T cells.

The induction of dendritic cell (DC) maturation is critical for the induction of Ag-specific T lymphocyte responses and may be essential for the development of human vaccines relying on T cell immunity. In this study, we have investigated the effects of monophosphoryl lipid A (MPL) on human monocyte-derived DC as well as peripheral blood T cells. Calcium mobilization, mitogen-activated protein kinase activation, and the NF-kappaB transcription factor were induced after MPL stimulation of DC and required high doses of MPL (100 microg/ml).