Suppression of autochthonous tumors by mixed implantation with Nocardia rubra cell-wall skeleton and related bacterial fractions.

Antitumor activities of the cell-wall skeleton of Nocardia rubra and related bacterial fractions in autochthonous tumor-host system were tested on autografts of spontaneous mammary adenocarcinoma in SHN mice and of 3-methylcholanthrene-induced fibrosarcoma in ICR/JCL mice. The oil-attached cell-wall skeleton of N. rubra was the most effective in suppressing the autografts of the mammary adenocarcinoma but less of the fibrosarcoma, when the autografts were mixed with oil-attached preparation and implanted subcutaneously in the original host, while peptidoglycolipid of Mycobacterium tuberculosis Aoyama B was the most suppressive on the autografts of the fibrosarcoma but not on the mammary tumor autografts. The cell-wall skeleton of Mycobacterium bovis BCG slightly suppressed the autografts of the fibrosarcoma. Presensitization of tumor-bearing mice with the cell-wall skeleton of N. rubra resulted in a more marked suppression on autografts of both tumors than without the presensitization, but local destruction of these tumor autografts did not induce recognizable systemic immunity to the respective tumors. Intralesional injection of cell-wall skeleton of N. rubra showed prolongation of survival days of mice with fibrosarcoma.