The invention provides a composition for modulating immunity by the in vivo targeting of an antigen to dendritic cells. The composition comprises: a preparation of antigen-containing membrane vesicles or antigen-containing liposomes which have on their surfaces a plurality of metal chelating groups； and, a ligand for a receptor on the dendritic cells, the ligand being linked to a metal chelating group via a metal affinity tag on the ligand. The composition further includes an immunomodulatory factor. A process for preparing the composition is also provided. The invention further provides a method of modulating an immune disorder, and methods of treating tumours and infections.
