Effect of BCG cell-wall skeleton on metastasis of syngeneic tumor in rats, with special reference to lymphocyte trapping.

Oil-attached BCG cell-wall skeleton (BCG-CWS) was demonstrated to have an activity inducing lymphocyte trapping in the draining node in rats. It acts also as a potent adjuvant for the lymphocyte trapping when injected into the growing syngeneic transplantable tumor. Treatment with repeated intratumor injections into the primary tumor resulted in suppression of tumor growth in both primary and metastatic sites. Even when the primary tumor escaped regression, inhibitory effect on metastatic spread was attained by the therapy. The contribution of BCG-CWS to suppression of metastasis especially in the draining node was discussed from the point of lymphocyte trapping in the draining node.