Abstract: A method for the production of activated tumor-specific T cells by co-cultivating, ex vivo, tumor cells from a patient with T cells from that patient, comprising the steps of: i) incubating the tumor cells with a first fusion protein obtained from a B7 protein and one partner of a biological binding pair and a second fusion protein obtained from an antibody against a cell surface antigen and the other partner of the biological binding pair, ii) inhibiting the proliferation of the tumor cells prior to or after that incubation; iii) co-cultivating the tumor cells with the T cells to be activated, until activation of the T cells is attained; iv) separating the activated T cells from the tumor cells, is highly efficient and can be carried out in a simple manner.