Differences in the apoptosis-inducing properties of VISCUM ALBUM L. extracts

Journal/Book: Anti-Cancer-Drugs 8 (suppl.1), 9-14. 1997;

Abstract: *Viscum* album L. (mistletoe) extracts are widely used in adjuvantcancer therapy. In contrast to purified components, such as mistletoelectins and viscotoxins, whole plant extracts of mistletoe resulted inDNA stabilization in cyclophosphamide-treated lymphocytes but alsoprovided cytotoxicity in tumour cells and lymphocytes. The killingcapacities of mistletoe extracts were host tree-specific and notcorrelated with mistletoe lectin or viscotoxin content. In humanlymphocytes, only mistletoe lectins induced a pathway of apoptotickilling. Within 72 h, the lectin B chains also increased the number oflymphocytes undergoing apoptosis. This finding suggests that inhibitionof protein synthesis by the A chain of the hololectin may accelerate areceptor-mediated killing pathway induced by the B chains. An unexpectedfinding was related to the mistletoe-mediated killing, which was moreeffective against CD8+ T cells with an activated phenotype than CD19+ Bcells and CD4+ T cells. In vitro treatment of human neutrophils withmistletoe resulted in a slight decrease of phagocytosis and burstactivity. The observed dose-dependent occurrence of two neutrophilsubsets with different burst activities indicates differences in theirsusceptibility to mistletoe and suggests the implication of an inductionof the apoptotic killing pathway.COPYRIGHT BY Elsevier Science BV, Amsterdam, Netherlands END OF DOCUMENT

Keyword(s): Medical:neutrophil

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