Immunity to transplanted tumour: The effect of tumour extracts on the growth of homologous tuamours in raits

Abstract

Rats bearing grafts of tumours originally induced within the same inbred strain of animals were treated with ethanol extract concentrates of the homologous tumours. The tumour extracts caused considerable tissue destruction when injected into growing tumors, although only a few of the treated tumours regressed completely. Where treated tumours regressed and the hosts remained free from recurrent growth of the original graft, the hosts were found to be immune to further implants of the same tumour. Treatment of rats with the tumour extract concentrates prior to implantation of tumourfailed to induceany immunity and the tumour grafts grew as rapidly as those in untreated animals. It is suggested that the development of tumour immunity depends upon the presence of immunogenetic differences in the tumour-host relationship and that the ethanol extracts of tumour tissue act as tumour destroying agents which inhibit tumour growth and so permit the development of immune processes. © 1955, The British Empire Cancer Campaign for Research. All rights reserved.