Ken Shortman’s main research interest is the dendritic cell (DC) system and its role in immune responses. He described some of the original DC subtypes, studied their distinct immune functions and mapped their development during haematopoiesis. With his colleagues Irina Caminschi and Mireille Lahoud he characterised novel DC surface molecules, including the dead cell recognition receptor Clec9A (also termed DNGR1 in related studies by the Reis e Sousa laboratory). Both laboratories recently identified the ligand of Clec9A as filamentous actin, exposed when the cell membrane is ruptured. A main research theme is now the use of Clec9A as target for enhancing immune responses. The eventual aim is to improve the effectiveness of vaccines by directing vaccine antigens to Clec9A on specific human DC subtypes.