Allogeneic bone marrow transplantation for the treatment of leukemia in patients with acute lymphocytic leukemia (ALL) is used with increasing frequency. However, one of the major shortcomings remains the risk of leukemic relapse. In ALL of mature T-cells (T-ALL) the variable region of the T-cell receptor (VB) is unique for all monoclonal tumor cells, thus representing a 'tumor defining antigen'. In order to induce a graft-versus-leukemia reaction directed specifically against these tumor cells, HLA-matched, CD8+ T-cells will be primed in vitro by autologous dendritic cells presenting recombinant VB tumor antigen. In vitro primed cytotoxic CD8+ T-cells will subsequently be tested for their ability to specifically kill the T-ALL cells from which the recombinant VB was derived. If so, this in vitro model would open new avenues in the protection from leukemic relapse of T-ALL patients after allogeneic bone marrow transplantation.