 evid immunolog reaction host direct activ grow primari tumor cell isol primari benzo pyren-induc fibrosarcoma rat pure test abil grow autograft inject autochthon host autograft primari tumor remov grew occasion anim major tumor left instanc sarcoma cell grew inject syngen recipi recipi growth sarcoma cell prevent retard mix vitro prior inject spleen cell anim immun tumor autochthon spleen cell anim tumor behav test immun anim long spleen 3 week remov tumor spleen tumor remov time autochthon spleen cell behav spleen cell immun anim interfer growth tumor autograft spleen cell experi rat react activ grow primari tumor tumor exhaust suppli lymphocyt respons reaction tumor remov concentr antitumor lymphocyt spleen build anim reject autograft -j nat cancer inst 36 29-35 1966 