It will be the purpose of the future experiments to find out whether the vaccination constructs employed played any role in the differentiation of CD4+ T cells into effector cells, whether the mouse strain mattered, and whether the effects we observed were associated with the presence of human p210bcr-abl in the mouse system or with the nature of the tumor cells expressing this protein, the key element in the pathogenesis of chronic myeloid leukaemia (CML). The gene discussed is CD4; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.