Alum interaction with dendritic cell membrane lipids is essential for its adjuvanticity

lum has long been used as a vaccine adjuvant, yet the mechanisms by which it increases antigen-specific immune responses remain unclear. Flach et al . now report that alum interacts with lipids in the plasma membrane of dendritic cells, resulting in nonphagocytic uptake of antigen and increased association with CD4 + T cells. These results suggest that, at least for dendritic cells, lipids rather than proteins may sense alum and trigger downstream signaling events that lead to enhanced T cell responses.