The present invention concerns a mammalian cell line which when co-cultured with lymphocytes during which allogenic stimulation is avoided activates lymphocytes fo form tumoricidal cells, a process for the production of tumoricidal T lymphocytes by co-culturing lymphocytes with this cell line, the tumoricidal T lymphocytes obtained by means of this process and the use of the cells according to the present invention for the production of a therapeutic agent which can be used in tumour therapy.