Prof dr Cornelis J.M. Melief, M.D., Ph.D, is a professor of internal medicine specialized in “immunohematology” at Leiden University and head of the LUMC’s Department of Immunohematology and Blood Transfusion, where he leads an internationally acclaimed group focusing on the elucidation of immunological mechanisms that can lead to effective clinically applicable T cell-based immunotherapy of cancer. He received his Ph.D. degree in 1967 from the University of Amsterdam, where he also received his M.D. degree in 1970. He spent two years (1973/1974) as a postdoctoral fellow at the New England Medical Center and Dana Farber Cancer Center (Harvard) in Boston. Of his many contributions to basic immunology, including work in mouse models, and clinical immunology, the most striking highlights are the eradication of large established mouse tumors by adoptive transfer of cytotoxic T lymphocyte clones against defined MHC class I presented peptides, and the discovery that T cell help for cytotoxic T lymphocyte induction involves cognate interaction between CD40 ligand on T helper cells and CD40 on Dendritic Cells. This is a major novel pathway of cytotoxic T lymphocyte induction in non-inflammatory conditions.