C. parvum treatment of transplanted rat tumours of spontaneous origin.

C. parvum (Wellcome CN6134) has been examined for suppression of a range of transplanted rat tumours of spontaneous origin. With five tumours (three mammary carcinomas and two fibrosarcomas) growth of comparatively high cell inocula (with respect to the minimum for growth in control rats) was suppressed by admixture with the vaccine. Equivalent dry weights of Glaxo, Pasteur or Connaught BCGs were relatively ineffective. Intralesional injection of C. parvum into three three established tumours (two mammary carcinomas and one fibrosarcoma) retarded development of only one, the mmamary carcinoma Sp4. With three mammary carcinomas and one fibrosarcoma, active specific immune stimulation with vaccines of viable or irradiated cells admixed with C. parvum was again consistently effective only with carcinoma Sp4, and this tumour was also susceptible to intradermal but not intravenous treatment with C. parvum alone.