The present invention is directed to delivery and retention of active agents to targeted lymph nodes in a mammal using a ligand/anti-ligand pair. More particularly, the invention involves methods, compositions, and kits for delivery and retention of active agents to targeted lymph nodes using compositions comprising a ligand-colloid moiety and compositions comprising an anti-ligand. Active agents may be associated with one or more of the colloid, ligand, or anti-ligand. Conjugation of the ligand and anti-ligand after administration permits retention of aggregated colloid complex in targeted lymph nodes.