Cellular and humoral cytotoxicity in patients with leukaemia and preleukaemia. II. Oncovirus specificity of the reaction.

Cytotoxic activities of lymphocytes and antibodies against autologous tumour cells detected by 51Cr release technique were frequent in patients with chronic granulocytic leukaemia, but infrequent in patients with blastosis of acute myeloid leukaemia. Among subjects with potentially preleukaemic haematological disorders autologous cytotoxic activity was observed only in cases of cytopenia, while samples from patients with polycythaemia vera proved to be devoid of cellular and humoral cytotoxicity. In the majority of cases the cytotoxic activity of lymphocytes and antibodies could be blocked by gp70 antigens of baboon endogenous virus (BaEV) and gibbon ape leukaemia virus (GaLV). p15(E) antigens of BaEV and GaLV showed blocking activity less frequently. Digestion by glycosidase of the carbohydrate of gp70 antigens reduced their blocking activity.