Antigenic changes of L5178Y lymphoma after treatment with 5-(3,3-dimethyl-1-triazeno) imidazole-4-carboxamide in vivo.

Immunologic alteration of the L5178Y lymphoma was obtained in vivo after treatment with 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DIC). A single dose of 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU) "CURED" MICE CHALLENGED WITH L5178Y cells that had been treated with DIC (L5178Y/DIC) for four transplant generations; BCNU did not cure mice bearing the parent tumor. The L5178Y/DIC, treated in vivo for five transplant generations, id not grow in syngeneic mice. L5178Y/OIC cell growth and incidences of death were similar to those of parent cells when inoculated into heavily immunosuppressed mice. Adoptive transfer of lymphocytes from spleens of mice sensitized to the drug-altered tumor specifically protected immunosuppressed mice bearing the L5178Y/DIC tumor. Little protection was afforded by lymphocytes immune to the parent L5178Y tumor, whereas nonimmune lymphocytes or lymphocytes immune against unrelated tumors were completely ineffective. Anti-L5178Y/DIC lymphocytes did not cure mice challenged with the parent L5178Y tumor. Irradiated (400 R) mice previously sensitized to L5178Y/DIC cells rejected 10(2)-10(7) inocula of L5178Y/DIC cells and died when the parent L5178Y was used for challenge. It was concluded that antigeni( alterations of L5178Y cells occurred in (BALB/ctcr X DBA/2Cr)F1 mice after treatment with DIC in vivo.