Therapeutic effect of cell-wall skeleton of Propionibacterium acnes in combination with a monoclonal antibody (C6-1.2) on the lung metastases of Lewis lung carcinoma.

Abstract

The purpose of this study was to determine whether the combination of C6-1.2 monoclonal antibody (MoAb) (established in our laboratory), which is specifically reactive with Lewis lung carcinoma (3LL), and cell-wall skeleton of Propionibacterium acnes C7 (P. acnes-CWS) would significantly decrease established spontaneous metastases of 3LL. C6-1.2 MoAb combined with intratumoral (or intralesional) injection of P. acnes-CWS, when administered at an early stage of the experiment, showed a significant reduction of lung metastases in 3LL-bearing mice. The treatment modality of C6-1.2 MoAb alone did not decrease the lung tumor colonies. On the other hand, the combined treatment of intravenous injection of P. acnes-CWS and C6-1.2 MoAb did not significantly reduce the lung metastases of 3LL tumors in 3LL-bearing mice compared with the treatment of P. acnes-CWS alone. In contrast, when the primary tumor was surgically removed, the most remarkable reduction of lung metastases was observed by the combination of intravenous administration of both C6-1.2 MoAb and P. acnes-CWS. We concluded that the antimetastatic activity of C6-1.2 MoAb and P. acnes-CWS varies depending on the injection route, and also that surgical excision of the primary tumor can lead to remarkable reduction of 3LL lung metastases.