CD4 and neoplasm: 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).