Radiosensitivity of the DS-carcinosarcoma of the rat as influenced by immune reactions

BDII rats obtained humoral antibodies in a xenogenetic or syngenetic immune serum or specific sensitised isogenetic immune cells for passive immunisation. Other animals were actively immunised with a so-called large dose of DS-carcinosarcoma extract or a so-called small dose of the tumour extract. The mode of irradiation was chosen in such a manner that even slight differences in the radiation sensitivity between immunised and non-immunised animals would as far as possible not be hidden by other factors. Thus when irradiating the tumours, one did without the administration of a dose which would have effected a best possible irradiation effect. A greater fractionation of the uniformly administered total dose of 2,000 R in the tests was also avoided. If the growth of a tumour can be inhibited by an immunologic influence of the tumour host relationship, then the radiation sensitivity of these cells is sumultaneously increased. If the specifically prepared immunity against tumours was not transfered to the test animals, no influence on the radiation sensitivity of the tumours was found. If the growth of the tumour accelerates, then a reduced radiation sensitivity of these tumours was simulated by the fast growth partly compensating the irradiation effect. A transfer of animal experimental investigations to the treatment of human cancer is still faced by great difficulties. The experience gathered in the last decades in the field of experimental tumour immunology are, however, important steps to this target. (orig./LH)