Effect of conagenin in tumor bearing mice. Antitumor activity, generation of effector cells and cytokine production.

Antitumor effects and function of T cells in tumor bearing mice given conagenin (CNG), a low molecular immunomodulator, were investigated. The administration of CNG, once a week for 4 weeks, was the most effective schedule in inhibiting growth of IMC carcinoma, a syngeneic tumor. In this regimen, cytotoxic T lymphocytes and natural killer activities in spleens of CNG treated mice were maintained at higher levels than those of non-treated mice. Lymphokine production by splenic T cells was also enhanced in cultures, whereas monokine production by macrophages, which was increased in accordance with tumor growth, was reduced by CNG administration. The antitumor effect of CNG was not observed in mice given anti-asialo GM1 serum and in athymic mice. Results shown in this report suggest that CNG exerts its antitumor effects through activation of T cells and enhancement of generation of antitumor effector cells.