Immunological mechanisms of antitumor activity of some kinds of crude drugs on tumor necrosis factor production

Previously, we described the antitumor activity of four crude drugs, A. capillaris, S. doederleinii, A. macrocephala and S. subprostrata. Tumor necrosis factor (TNF) can be produced in animals by injecting Bacillus Calmette-Guerin (BCG) or Corynebacterium parvum (CP) as priming agents and endotoxin (LPS) as an eliciting agent. However, because of their severe toxic action, it is inappropriate to use these agents to induce intrinsic TNF in cancer patients. In the present paper, we began with the investigation of a fluorometric method using ethidium bromide (EB) to assay TNF activity in serum in vitro, and then examined whether the four crude drugs displayed the priming and eliciting activities for TNF production. The TNF activity in a serum sample could be titrated using the fluorometric method in addition to a method using 3H-thymidine. The fluorometric method was superior to the radio-method as regards simplicity, safety and reproducibility. A. capillaris, S. doederleinii and S. subprostrata showed priming activity for TNF production in mice without the liver and spleen hyperplasia seen in the case of CP, S. subprostrata showed an eliciting activity in CP-primed mice. These results suggest that the crude drugs might be useful as inducers of intrinsic TNF in cancer patients.