INDUCTION OF ANTITUMOR IMMUNITY IN SYNGENEIC MICE BY A LEUKEMIC-CELL LINE

Induction of anti-tumour immunity in syngeneic mice by LBC cell line d erived from a non-immunogenic T cell leukaemia was studied. The immuni zation of BALB/c mice with LBC irradiated cells induced in them anti-t umour spleen cells, cytotoxic T lymphocytes and anti-LBC antibodies. T he anti-LBC antibodies reacted with components of 14, 16 and 27 kDa pr esent on LB tumour cells, LBC cell line and normal thymocytes, but not with normal lymph node cells. Furthermore, immunization of the autolo gous hosts with LBC cells partially protected them against subsequent challenge with the original LB leukaemic cells. These findings demonst rate that culture conditions induced modifications in the antigenic pr operties of the leukaemic cells, allowing LBC cells to stimulate an im mune response directed against components expressed at early stages du ring T cell maturation. These results also suggest that the immune res ponse is responsible for the prolongation of the survival time of the mice inoculated with the parental leukaemic cells.