The effects of telocinobufagin isolated from Chan Su on the activation and cytokine secretion of immunocytes in vitro.

Many traditional Chinese medicines have been used as immunomodulators that act as either immunosuppressants or immunostimulators. Recently, our lab successfully isolated a monomer telocinobufagin (TCB) from the chloroform extract of Chan Su (Venenum Bufonis). In the present paper, we evaluated the immunomodulatory effects of this compound in vitro. We found that TCB significantly stimulates splenocyte proliferation when administered alone or in combination with polyclonal T-cell mitogens concanavalin A (Con A) and lipopolysaccharide. Telocinobufagin markedly enhances natural killer cell and peritoneal macrophage activation. Telocinobufagin increases the percentage of CD4, CD8 positive cells within a population of splenocytes. Moreover, we found that the level of several Th1 cytokines, including interleukin-2 (IL-2), interleukin-12 (IL-12), interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), are significantly increased after TCB treatment, while the level of the Th2 cytokine interleukin-4 (IL-4) is significantly decreased. As a result, the ratio of Th1/Th2 is significantly increased. Taken together, these results indicate that TCB has potential immune system regulatory effects and suggest that this compound could be developed as a novel immunotherapeutic agent to treat cancer and other immune-mediated diseases, and it may become a new immunomodulatory agent in many regions.