Concomitant immunity against tumor development is enhanced by the oral administration of a kampo medicine, Hochu-ekki-to (TJ-41: Bu-Zhong-Yi-Qi-Tang).

The oral administration of a kampo herbal medicine, Hochu-ekki-to (TJ-41: Bu-Zhong-Yi-Qi-Tang) using a water-supplying bottle resulted in a slight but significant inhibition of Meth A growth. The oral administration of TJ-41 with gastric gavage significantly enhanced the specific antitumor activity against Meth A at rechallenge on day 9. In a tumor-neutralizing assay, the tumor draining LN cells of the TJ-41 administered mice showed an antitumor activity against Meth A. In a cytolytic assay, the anti-Meth A specific cytolytic T lymphocyte activity was not detected in the spleen cells of the Meth A bearing and TJ-41 administered mice. The oral administration of TJ-41 enhanced the natural killer (NK) activity of the spleen cells in naive mice but could not improve the decreased NK activity of spleen cells from the tumor bearing mice. In a cytostatic assay, the peritoneal exudate cells from the Meth A bearing and TJ-41 administered mice showed a significantly higher amount of cytostatic activity against Meth A than that from either Meth A bearing or TJ-41 administered mice. These results indicate that the oral administration of TJ-41 into the tumor bearing mice may thus be able to enhance concomitant antitumor immunity through the augmentation of the cytostatic activity.