Mediation of human NK-activity by components in extracts of VISCUM ALBUM
Journal/Book: Int. J. Immunopharmac. 9 (2), 199-209. 1987;
Abstract: Viscum album extracts (Iscador) were investigated for their potency toinfluence NK cytotoxicity in vitro. In vitro short term cytotoxicityassays (4 h) with human peripheral mononuclear cells (PMNC) and human K562 tumor cells showed a drastic enhancement of NK cytotoxicity in thepresence of V. album extracts. The presence of the V. album componentsduring tumor cell lysis was essential since preincubation of PMNC withV. album extract followed by thorough washing did not lead toenhancement of NK cytotoxicity. One responding effector cell wasidentified as a member of the large granular lymphocyte (LGL) familycarrying both Leu 7 and Leu 11 surface markers. Furthermore, monocytesdepleted of LGL, but not differentiated macrophages, showed a weakenhancement of their cytolytic activity in the presence of V. albumextract. Fractionation of V. album extracts revealed two activefractions one (C1) with about 3-4000 D and the other (C2) less than 1000D. Both components enhanced NK cytotoxicity of LGL (Leu 7+, Leu 11+) aswell as of monocytes showing enhancing effects also against moderatelyNK-sensitive tumor cell lines. Author.