Cytotoxicity of lymphocytes and antibodies against autologous tumor cells in patients with myeloid leukaemias and preleukaemic disorders. III. Stage-dependence of oncovirus-specific immune response.

: Lymphocyte and plasma samples from the quiescent and blastic phase of chronic granulocytic leukaemia (CGL) and from the blastosis and remission of acute myeloid leukaemia (AML), were compared for cytotoxic activity. Target cells were collected from the blastic phases of diseases. 51Cr-release tests showed that the lymphocytes and plasma samples from blastic crisis of CGL had no cytotoxic activity for autologous blast cells. In contrast, cryopreserved lymphocytes and plasmas from the quiescent phase of CGL proved to be cytotoxic for the autologous tumor cells, and their effect could be blocked by native gp70 antigens of gibbon ape leukaemia virus (GaLV) and baboon endogenous virus (BaEV). A blocking effect was less frequently exerted by carbohydrate-free gp70 and p15(E) antigens. A similar relationship was found between the blastosis and remission stage of AML, however, out of the antigens of BaEV only the native gp70 showed a marked blocking effect.